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CONTRpL DATA 
CORPORATION 



SPEC 77738212 

CD 8 

REV F 

DATE August 1988 

PAGE 1 of 59 



PRODUCT SPECIFICATION 

FOR 

TM 

WREN III DISK DRIVE 
MODEL 94166 



COPYRIGHT (?) 1988 

by CONTROL DATA CORPORATION 

ALL RIGHTS RESERVED 

Printed in the United States of America 



This publication may contain application, high technology, 
or product specification data, or any combination thereof, 
is considered advance technical information by the 
producer, and is subject to change without prior notice. 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-D 

SUMMARY 

TM 

The CDC WREN Peripheral family is composed of the following members. 
For specific information on each member, refer to the appropriate 
documents. 



1 NAME 


MOOEL 
NUMBER * 


PRODUCT 

SPECIFICATION 


INTERFACE 


CAPACITY 
(MEGABYTES) 


| WREN II 
| WREN II 
| WREN II 
| WREN II HH 


94155-XX 
94156-XX 
94151-YY 
94205-XX 


77715909 
77738019 
77738208 
77738161 


CDC 506 (ST506 C0MP.) 

ESDI 

SCSI (SASI™ Subset) 

C0C 506 (ST506 C0MP.) 


48, 57, 67, 77 or 36 
46, 67 or 86 

25 to 80 
30, 41 or 51 


| WREN III 
i WREN III 


94166-XXX 

94161-YYY 


77738212 
77738270 


ESDI 
SCSI ** 




101, 141 or 182 

86, 121 or 155 (512 Byte) 


(WREN III HH 
|WREN III HH 


94211 -YY 
94216-XXX 


77765250 
77765276 


SCSI ** 
ESDI 




91 (512 Byte) 
106 


1 WREN IV 


94171-YYY 


77738386 


SCSI ** 




307 (512 3vte) 



* XX(X) denotes unformatted drive capacity in megabytes. Foe 
example. Model number 94166-182 is a WREN III with ESDI Interface 
and an unformatted capacity of 182 megabytes. 

YY(Y) denotes formatted drive capacity. 

** These drives allow the user to reformat using any integer data 
block size between 256 and 2048 bytes. Units are normally 
formatted at the factory with 512 byte data block size, with 
capacity dependent on number of data heads. 



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PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-C 

TABLE OF CONTENTS 

1 . SCOPE 6 

2 . APPLICABLE DOCUMENTS 6 

2 . 1 STANDARDS 6 

2 . 2 DOCUMENTATION 7 

2.2.1 Applicable Documents 7 

2.2.2 Ref lected Changes 7 

3.0. GENERAL DESCRIPTION 8 

4 . FEATURES 10 

4 . 1 STANDARD FEATURES 10 

4 . 2 OPTIONAL CONFIGURATIONS 10 

4 . 3 OPTIONAL ACCESSORIES (USER INSTALLED) 10 

5 . PERFORMANCE CHARACTERISTICS 11 

5 . 1 ACCESS TO DATA CHARACTERISTICS 12 

5.1.1 Seek Time 12 

5.1.2 Spindle Speed and Latency 13 

5 . 2 READ DATA TRANSFER RATE 13 

5 . 3 START/STOP TIME 13 

6.0 RELIABILITY SPECIFICATIONS. 13 

6 . 1 ERROR RATES 14 

6.1.1 Read Errors 14 

6.1.2 Environmental Interference 15 

6.1.3 Write Errors 15 

6.1.4 Seek Errors 15 

6.2 RELIABILITY AND SERVICE 16 

6.2.1 Mean Time Between Failure 16 

6.2.2 Preventive Maintenance 16 

6.2.3 Service Life 16 

6.2.4 Service Philosophy 16 

6.2.5 Installation 16 

6.2.6 Service Tools 16 

7 . PHYSICAL/ELECTRICAL SPECIFICATIONS 17 

7.1 AC POWER REQUIREMENTS 17 

7.2 DC POWER REQUIREMENTS 17 

7.2.1 Power Sequencing 18 

7.2.2 12 V Current Profile 18 

7 . 3 HEAT/POWER DISSIPATION 19 

7 . 4 ENVIRONMENTAL LIMITS 19 

7.4.1 Temperature 19 

7.4.2 Relative Humidity 20 

7.4.3 Effective Altitude 20 

7.4.4 Shock and Vibration 20 

7.4.5 Air Cleanliness 24 



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PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-C 

TABLE OF CONTENTS (continued) 

7 . 5 MECHANICAL SPECIFICATIONS 25 

7.5.1 Dcive Orientation 26 

7.5.2 Cooling 26 

8.0 MEDIA CHARACTERISTICS 26 

8.1 MEDIA DESCRIPTION 26 



9 . DEFECT AND ERROR MANAGEMENT 2 



10 . INTERFACE CABLING REQUIREMENTS /OPTIONS 28 

10 . 1 RADIAL CONFIGURATION 28 

10 . 2 DAISYCHAIN CONFIGURATION 28 

10 . 3 DC CABLE AND CONNECTOR 29 

10 . 4 DATA CABLE AND CONNECTOR 30 

10 . 5 CONTROL CABLE AND CONNECTOR 33 

10 . 6 INTERFACE DRIVERS /RECEIVERS 33 

10.6.1 Single Ended Drivers/Receivers 33 

10.6.2 Balanced Differential Drivers/ 
Receivers 36 

10.7 SIGNAL/CHASSIS GROUNDS 37 

11.0 SERIAL MODE INTERFACE SIGNAL DESCRIPTION 3 9 

11. 1 CONTROL INPUT LINES 39 

11.1.1 Drive Select 39 

11.1.2 Head Select 2°, 2 1 . 2 2 . and 2 3 40 

11.1.3 Write Gate 42 

11.1.4 Read Gate 42 

11.1.5 Command Data 42 

11.1.6 Transfer Request 48 

11.1.7 Address Marie Enable 48 

11 . 2 CONTROL OUTPUT LINES 48 

11.2.1 Drive Selected 48 

11.2.2 Ready 48 

11.2.3 Conf ig/Status Data 48 

11.2.4 Transfer Ack 55 

11.2.5 Attention 55 

11.2.6 Index 55 

11.2.7 Sector/Address Mark Found 55 

11.2.8 Command Complete 55 

11 . 3 DATA TRANSFER LINES 56 

11.4 READ. WRITE, AND FORMAT PARAMETERS 56 

11.5 DEFECTS LIST 57 



-4- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 

TABLE OF CONTENTS (continued) 

12 . OPTIONS 57 

12 . 1 DRIVE CONFIGURATION SWITCHES 57 

12 . 2 FRONT PANEL 59 

12 . 3 CUSTOM FORMATTING 59 

12 . 4 SOFT SECTOR OPTION 59 

12.5 SINGLE UNIT SHIPPING PACK 59 

13.0 ACCESSORIES 59 

13 .1 FRONT PANEL KIT 59 

13 .2 SINGLE UNIT SHIPPING PACK KIT 5 9 



-5- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 



1.0 



SCOPE 

This specification describes the Control Data Corporation 
Model 94166 WREN™I1I Disk Drive. This 5 1/4-inch member of 
the rigid disk family supports the Enhanced Small Device 
Interface (ESDI) and is offered in three different 
capacities. The basic configurations are Listed in section 
4.2 of this specification. 




2.0 

2.1 



FIGURE 1. 94166-XX(X) WREN III 

APPLICABLE DOCUMENTS 

STANDARDS 

The WREN III has been developed as a system peripheral to 
the highest standards of design and construction. The WREN 
III depends upon its host equipment to provide adequate 
power and environment in order to achieve optimum 
performance and compliance with applicable industry and 
governmental regulations. Special attention must be given 
in the areas of safety, power distribution, shielding, 
audible noise control, and temperature regulation. 



-6- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-C 

2.1 (continued) 

The WREN III complies with CDC standards as noted in the 
appropriate sections of this specification. 

The WREN III is a UL Recognized component per UL478 and a CSA 
Certified Component per CSA C22.2. No. 154-M1983. It also meets 
the requirements of DIN IEC380/VDE0806/8 . 81. 

The WREN III. as delivered, is designed for system integration 
before use. It is supplied as a Class A Computing Device per 
the FCC Rules and Regulations. Part 15. Subpart J governing EMI 
of computing devices. 

CAUTION 

To avoid potential repair problems, observe the following 
precautions: 

• Labels must not be put over the breather holes on the top of 
the drive. 

• If a label has been placed over the breather holes, do not 
poke holes through the label, as the filter underneath is 
certain to be damaged, allowing contamination to enter. 
REMOVE THE LABEL. Do not use solvents to remove the adhesive 
residue. Small amounts of solvent may migrate down the 
breather holes and contaminate the disk. 

• CDC/MP1 factory installed labels must not be removed from 
the drive or covered with additional labels, as they contain 
information required when repairing. 

• DC power should not be switched on to the drive by plugging 
an electrically "live" DC source cable into the drive power 
connector. This practice adversely affects the reliability 
of the connector contacts. 

2.2 DOCUMENTATION 

2.2.1 Applicable Documents 

The documents listed below are referenced in this specification. 

77738216 OEM Manual 

77738076 CDC ESDI Specification 

2.2.2 Reflected Changes 

Changes to individual pages of this specification are reflected 
in the revision letter at the top right corner of the page, 
after the part number. The revision letter applies to that page 
only and does not change unless a change was made on the page, 
in which case it takes the latest revision letter of the 
specification. In comparing different revisions of the 
specification, note that the pages with the same revision 
letters as the specification were the ones changed to achieve 
that particular specification revision. 

-7- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 



3.0 GENERAL DESCRIPTION 

The WREN III is a member of a family of low cost, high 
performance, highly reliable, random access storage devices 
designed to meet the needs of the OEM marketplace. 

The WREN III is designed to record and recover data on 
three, four, or five 5-1/4 inch (130 mm) fixed disks. It 
does not have removable media capability. 

The Model 94166 WREN III supports the Enhanced Small Device 
Interface (ESDI) as described in Control Data's ESDI 
Specification (77738076). This product specification was 
created to be used in conjunction with this industry stan- 
dard interface specification. The information contained in 
these two documents defines the product performance char- 
acteristics and the interface characteristics of the Model 
94166 WREN III. 

The WREN III is designed to support the Serial Mode of ESDI 
Operation. 

The head, disk and actuator chamber is environmentally 
sealed at the factory. Air is recirculated within the HDA 
through a nonreplaceable filter to maintain a contamination 
free disk/actuator environment. 

Refer to Figure 2 for an exploded view of the WREN III. 
NEVER disassemble the WREN Head/Disk Assembly (HDA) . This 
exploded view is for information only. Servicing items in 
the sealed environmental enclosure (heads, media, actuator, 
etc.) requires special facilities. The printed circuit 
boards and hardware external to the sealed area may be 
replaced without special facilities. 

The WREN III uses a dedicated landing zone at the innermost 
radius of the media thus eliminating the possibility of 
destroying or degrading data by landing in the data zone. 

The WREN III incorporates an automatic shipping lock which 
prevents potential damage to the heads and disks caused by 
movement during shipping and handling. The shipping lock is 
automatically disengaged when power is applied to the drive. 

The WREN III decodes Track location from the dedicated 
servo surface thereby eliminating mechanical transducer 
adjustments and related reliability concerns. 

The WREN 111 uses a high performance actuator assembly 
consisting of a low inertia, balanced, straight arm (Patent 
Pending) which provides excellent performance with minimal 
power dissipation. 

-8- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 




V.HH0Ka_) 



FIGURE 2. Model 94166 WREN III 



-9- 



PRODUCT SPECIFICATION FOR tfREN III DISK DRIVE MODEL 94166 77738212-B 

4 . FEATURES 

4.1 STANDARD FEATURES 

The Model 94166 WREN III tias the following standard 
features: 

Industry standard Interface 

Data recovery circuitry contained in the drive 

Multiple capacity configurations 

Sealed head. disk, and actuator (HDA) chamber 

No preventive maintenance required 

LSI circuitry for high reliability 

Low audible noise for office environments 

Vertical or horizontal mounting 

Low power consumption 

Balanced low mass rotary voice coil actuator 

Automatic shipping lock 

Terminators 

Integral HDA shock and vibration isolation mounts 

Dedicated head landing zone 

Dynamic spindle braking 

4.2 OPTIONAL CONFIGURATIONS 

The following optional capacities are available as a 
factory installed option. 

Model 94166-182 182 MB 

Model 94166-141 141 MB 

Model 94166-101 101 MB 

The following options are incorporated at the time of 
manufacture when specified for delivery. (See Section 12.0.) 

• Front Panel with indicator - (See Figure 5) 

• Custom Formatting 

• Single Unit Shipping Pack 

• Soft Sector Operation 

4.3 OPTIONAL ACCESSORIES (USER INSTALLED) 

The following accessories are available to the user to 
facilitate his needs. All kits may be installed in the 
field. (See Section 13.0.) 

• Fcont Panel Kit and indicatior - (See Figure 5) 

• Single Unit Shipping Pack Kit 



-10- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 



5.0 PERFORMANCE CHARACTERISTICS 

Model 94166 WREN III capacity (unformatted) 

• Model 94166-182 182,094.480 Bytes (unformatted) 

160.745.470 Bytes (formatted*) 
5 Disks per Drive 
9 Data Surfaces 

• Model 94166-141 141.629.040 Bytes (unformatted) 

125.024.250 Bytes (formatted*) 

4 Disks per Drive 
7 Data Surfaces 

• Model 94166-101 101.163.600 Bytes (unformatted) 

89.303.040 Bytes (formatted*) 
3 Disks per Drive 

5 Data Surfaces 

Data Capacity Parameters (Unformatted) 

Maximum Number 9 

of Data Heads 

Bytes/Track 20.880 Bytes 

Bytes/Surface 20,232.720 Bytes 

Tracks/Surface 969 Tracks 

Tracks/Inch 960 TPI 

Bits/Inch 19.058 BPI 

Recording Code 2, 7 

Data Transfer Rate 10.0 Megabits/sec 

(1.25 Megabytes/sec) 

Data Bit Clock Period(R^c) 10 ° ns ± 1-0* 
(Reference/Read Clocks) 

Read Propagation Delay 7 to 9 Bit Times 

Write Propagation Delay 4 to 6 Bit Times 



*Based on 36 sectors with 512 Data Bytes each. 
Consideration for defect management not included 



-11- 



PRODUCT SPECIFICATION FOE WREN III DISK DRIVE MODEL 94166 77738212-B 



5.0 



PERFORMANCE CHARACTERISTICS (continued) 



Data Interface 
Rotational Speed 
Rotational Period 
Average Latency 
Single Track Seek Time 

Average Seek Time 



Maximum Seek Time 
(969 Tracks) 



NRZ Encoded Data 

3597 r/min +0.5% 

16.68 ms + 0.5% 

8.34 ms 

Typical 4 ms - NOTE 3 
Maximum 5 ms - NOTES 1 & 2 

Typical 16.5 ms - NOTE 3 
Maximum 18 ms - NOTES 1 & 2 

Typical 40 ms - NOTE 3 
Maximum 43 ms - NOTES 1 & 2 



NOTE 1: See Seek Command Description 11.1.5.1. 

NOTE 2: Maximum times are specified over the worse 

case conditions of temperature, voltage 
margins and drive orientation. All seek 
times include settle time. When comparing 
seek times, care should be taken not to mix 
typical seek times with maximum seek times. 
The only true comparison is with system 
benchmark tests. 

NOTE 3: Typical seek values are measured under 

nominal conditions of temperature, voltage, 
and horizontal orientation as measured on a 
representative sample of drives. All seek 
times include settle time. 

5.1 ACCESS TO DATA CHARACTERISTICS 

5.1.1 Seek Time 

Seek time is defined as the elapsed time from the receipt 
of a seek command until the drive signals the controller 
that it is ready to perform another seek or cead/write 
function on the new cylinder. Average seek time is 
determined by dividing the sum of the times foe all 
possible movements by the total number of movements. See 
also paragraphs 11.1.5.1 and 13.1.1.6. 



-12- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 9416 6 7773 82 12 -E 

5.1.2 Spindle Speed and Latency 

The spindle speed is 3597 +0.5% r/min. The speed tolerance 
includes motor performance and motor control circuit 
tolerances . 

The average latency time is 8.34 milliseconds, based on a 
nominal disk speed of 3597 r/min. The maximum latency time 
is 16.76 milliseconds based on a minimum disk speed of 3579 
r/min. 

5.2 READ DATA TRANSFER RATE 

The read serial data transfer rate is 10.0 Megabits per 
second. 1.25 Megabytes per second. 

5.3 START/STOP TIME 

The WREN III will become ready less than 35 seconds after 
application of DC power. Stop time will be less than 30 
seconds after removal of DC power. 

There is no power control switch on the WREN III. 

6.0 RELIABILITY SPECIFICATIONS 

The following reliability specifications assume correct 
host/drive operational interface has been implemented, 
including all interface timings, power supply voltages, and 
environmental conditions. 

Error Rates 

Soft Read Errors Less than 1 in 10 10 

(Recoverable) bits transferred 

Hard Read Errors Less than 1 in 10^ 2 

(Unrecoverable) bits transferred 

Seek Errors Less than 1 in 10 6 seeks 

MTBF 40.000 hours 

Service Life 5 years or 30.000 hours 

Preventive Maintenance None required 



-13- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94156 77738212-B 

6 . 1 ERROR RATES 

The error cates stated in this specification assume the 
following: 

a. WREN III is operated per this specification using DC 
Power as defined in this specification (see Section 
7.2) . 

b. A data format is employed fulfilling the requirements 
of the WREN III as outlined in the CDC ESDI 
Specification. 

c. Errors caused by media defects or host system 
failures are excluded from error rate computations. 
Refer to paragraph 8.0. Media Characteristics. 

6.1.1 Read Errors 

Before the determination of read error rates: 

a. The data which is to be used foe a measurement of 
read error rates must be verified as being written 
correctly on the media. 

b. All media defect induced errors must be excluded from 
error rate calculations. 

A recoverable read error is one that can be read correctly 
in 2 sets of 10 retries. After 10 retries, a recalibrate 
(RT2) and reseek to the suspected cylinder must be 
accomplished. The recoverable read error rate for any read 
operation shall be less than one error in 10 10 bits read. 

An unrecoverable read error is one that cannot be read 
correctly in 2 sets of 10 retries. The unrecoverable read 
erroc rate for any read operation shall be less than one 
bit in lO 2 - 2 bits read. 

Retries should use a combination of early and late data 
strobes as well as plus and minus actuator offsets. 



-14- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 



6.1.2 Environmental Interference 

When evaluating systems operation under conditions of 
Electromagnetic Interference (EMI), the performance of the 
WREN III within a system shall be considered acceptable if 
the device does not generate an unrecoverable error or 
cause an unrecoverable condition. 

An unrecoverable error, or condition, is defined as one 
which: 

1. Is not detected and corrected by the device itself; 

2. Is not capable of being detected from the error or 
fault status provided through the device/system 
interface; 

3. Is not capable of being recovered by normal device or 
system recovery procedures without operator 
intervention. 

6.1.3 Write Errors 

Write errors can occur as a result of the following: write 
data not being presented correctly, media defects, 
environmental interference, or equipment malfunction. As 
such, write errors are not predictable as a function of the 
number of bits passed. 

If an unrecoverable write error occurs because of an 
equipment malfunction in the WREN III, the error is 
classified as a failure affecting MTBF. Unrecoverable write 
errors are those which cannot be corrected within two 
attempts at writing the record with a read verify after 
each attempt, (excluding media defects). 

6.1.4 Seek Errors 

A seek error is defined as a failure of the WREN III to 
position the heads to the addressed track when the correct 
information has been presented to the WREN III. This 
condition must be determined by the controller by reading 
headers. There shall be no more than one recoverable seek 
error in 10 6 physical seek operations. A recoverable seek 
error is a positioning error which can be corrected by 
issuing a RTZ command and then reseeking the addressed 
track. Unrecoverable seek errors are classified as failures 
for MTBF calculations. 



-15- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-E 

6.2 RELIABILITY AND SERVICE 

6.2.1 Mean Time Between Failure 

The Mean Time Between Failure (MTBF) shall exceed 40,000 
hours for the WREN III. MTBF is defined as "Operating 
Hours'* divided by the "Number of Drive Failures". 

"Operating Hours" means total power on hours less any 
maintenance time. "Drive Failure" means any stoppage or 
substandard performance of the drive because of equipment 
malfunction, excluding stoppages oc substandard performance 
caused by operator error. adverse environment. power 
failure. controller failure. cable failure, oc other 
failure not caused by equipment. 

The term drive failure implies that maintenance is required 
because of a hardware failure. 

6.2.2 Preventive Maintenance 

No routine scheduled preventive maintenance shall be 
required. 

6.2.3 Service Life 

The WREN III shall have a useful service life of five years 
or 30.000 hours, whichever occurs first, before requiring 
factory refurbishment. Depot repair or replacement of major 
parts will be permitted during the lifetime (6.2.4). 

6.2.4 Service Philosophy 

Special equipment and environment is required to repair the 
WREN III HDA. Repairs may be performed only at a properly 
equipped and staffed depot service and repair facility. 

6.2.5 Installation 

The WREN III is designed, manufactured, and tested with a 
"Plug in and Play" installation philosophy. This philosophy 
minimizes the requirements for highly trained personnel to 
integrate the WREN III into an OEM's system, whether in a 
factory or field environment. 

6.2.6 Service Tools 

No special tools are required for site installation and 
none are recommended for site maintenance. Refer to 
paragraph 6.2.4. If field repair of items external to the 
HDA is desired, two sizes of 6 point Totx drivers (T10 and 
T15) are required. They may be purchased through most 



commercial tool catalogs. 



-16- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-C 



7.0 

7.1 

7.2 



PHYSICAL /ELECTRICAL SPECIFICATIONS 

AC POWER REQUIREMENTS 

None 

DC POWER REQUIREMENTS 

The voltage and current requirements for a single WREN III 
are shown in the following table. Values indicated apply at 
the drive power connector. 



TABLE 1. DC POWER REQUIREMENTS 



A 



Voltage 

Regulation 

Noise Immunity /^l± * 

Maximum Operating Current a /1\ 

Average Idle Current /l\/4\ 

Maximum Starting Current (Peak) 



| +5 V 


+12 


v A 


| +5% 
I 100 mV 


+ 5% 
100 


mV 


| 1.0 A 


2.3 


A 


i 0.8 A 


1.4 


A 


1 1.4 A 


4.5 





/2\ 






Measured with average reading DC ammeter. 

A +10% tolerance is permissible during power up. 
The ±5% must be maintained commencing with 
UNIT READY. 

Noise is specified as periodic and random 
distribution of frequencies covering a band from 
DC to 10 MHz. Peak to peak values are listed. 
See +12V current profile Level T6 in Figure 3A. 



NOTE 1: 

At powerup, the motor current regulator will limit the 12 
volt current to a peak value of less than 4.5 amps. 
NOTE 2: 

Minimum current loading for each supply voltage is not 
less than 30% of the average operating current shown in 
Table 1. 
NOTE 3: 

The +5 V and +12 V returns are tied together in the 
drive, but separate returns to the power supply should be 
used to minimize noise coupling between the supplies. 
NOTE 4: 

Where power is provided to multiple drives from a common 
supply, careful consideration for individual drive power 
requirements should be noted. Where multiple units are 
powered on simultaneously, the peak starting current must 
be available to each device. (Reference Table 1). 

-17- 



PRODUCT SPECIFICATION FOR WREN III "DISK DRIVE MODEL 94166 77738212-B 

7.2.1 Power Sequencing 

Powec sequencing is not required foe Che WREN III. The 
drive protects against inadvertent writing during power up 
and down. Daisychain operation requires that power be 
maintained on the terminated unit to ensure proper 
termination of the peripheral I/O cables. 

7.2.2 12 V Current Profile 

Figure 3A identifies the WREN III 12 V current profile. The 
current during the various times is as shown: 

Tl Power is initially applied to the drive and the 
spindle begins to accelerate under current limiting. 

T2 The spindle continues to accelerate under current 
limiting conditions. 

T3 The arm restraint solenoid is released. 

T4 The spindle is up to speed (3597 r/min) . 

T5 The autoveLocity adjust sequence is performed. 

T5 Velocity is set and the WREN is ready for reading and 
writing. 

T7 Power is removed from the WREN. 

NOTE 

All times and currents are typical. See 
Table 1 for maximum current requirements. 



4.0 A 

2.2 A 

1.4 A 



Tl 



T2 



T4 



T5 



T7 



2.3 A ?K 



2.5 A PK 




i 1 



1 



2.7 SEC 



12 14 15 
C'HH028a^ 

FIGURE 3A. TYPICAL WREN 111 +12 V CURRENT PROFILE 



-18- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 



7.3 HEAT/POWER DISSIPATION 

Each WREN III will dissipate no more than 33.0 watts (113 
BTUs per hour) of DC power average. Typical power 
dissipation under idle operating conditions is less than 21 
watts. 

7.4 ENVIRONMENTAL LIMITS 

Temperatures and humidity specifications preclude 
condensation on any drive part. Altitude and atmospheric 
pressure specifications are referenced to a standard day at 
58.7°F (14.8°C). Maximum Wet Bulb temperature is 82°F 
(28°C) . 

7.4.1 Temperature 

a. Operating 

50°F to 122°F (10°C to 50°C) operating ambient with a 
maximum gradient of 18°F (10°C) per hour. Above 1000 
feet (305 metres) altitude the maximum temperature is 
derated linearly to 112°F (44.4°C) at 10.000 feet 
(3048 metres). Cabinet packaging designs must provide 
ample air circulation around the WREN III to ensure 
environmental limits are not exceeded as a result of 
heat transfer from other system components. Operating 
ambient for specification purposes is defined as the 
environment immediately surrounding the WREN III. The 
temperature of the base deck must not exceed 135°F 
when measured at the isolation mount adjacent to the 
front panel LED. 

b. Transit 

-40° to 158°F (-40° to 70°C) package ambient with a 
maximum gradient of 36°F (20°C) per hour. This 
specification assumes that the drive is packaged in 
the shipping container designed by CDC for use with 
WREN III. 

c. Storage 

14° to 130°F (-10° to 54°C) device ambient with a 
maximum gradient of 27°F (15°C) per hour. 



19- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 

7.4.2 Relative Humidity 

a. Operating 

8% to 80% relative humidity with a maximum gradient 
of 10% pec hour. 

b. Transit 

5% to 95% relative humidity. 

c. Storage 

8% to 90% relative humidity. 

7.4.3 Effective Altitude (Sea Level Reference) 

a. Operating 

-1000 to +10,000 feet (-305 to +3048 metres) 

b. Transit 

-1.000 to +40,000 feet (-305 to +12,210 metres) 

c. Storage 

-1000 to +10.000 feet (-305 to +3048 metres) 

7.4.4 Shock and Vibration 

Shock and vibration limits specified in this document are 
measured directly on the drive chassis. If the WREN III is 
installed in an enclosure to which the stated shock and/or 
vibration criteria is applied, resonances may occur 
internally to the enclosure resulting in WREN III movement 
in excess of the stated limits. If this situation is 
apparent, it may be necessary to modify the enclosure to 
minimize WREN III movement. 

The limits of shock and vibration defined within this 
document are specified with the drive mounted by any of the 
four methods shown in Figure 3B. 



-20- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 777 3 8212-B 




4 SCREWS 

.2« in max) 

8. 1 mm 





) ^ 



^HHOl 3a j 



FIGURE 3B. RECOMMENDED MOUNTING 



-21- 



PRODUCT SPECIFICATION FOR WREN 111 DISK DRIVE MODEL 94166 77738212-B 

7.4.4.1 Shock 

a. Operating Normal 

Equipment, as installed foe normal operation, snail 
comply with the complete specified performance while 
subjected to intermittent shock not exceeding 2 g at 
a maximum duration of 10 ms (Half sinewave). Shock 
may be applied in the X, Y, or Z axis. Shock is not 
to be repeated more than two times per second. 

b. Operating Abnormal 

Equipment, as installed for normal operation, shall 
not incur physical damage while subjected to 
intermittent shock not exceeding 6 g at a maximum 
duration of 10 ms (half sinewave). Shock occurring at 
abnormal levels may promote degraded operational 
performance during the abnormal shock period. 
Specified operational performance will continue when 
normal operating shock levels resume. Shock may be 
applied in the X. Y, or 2 axis. Shock is not to be 
repeated more than two times per second. 

c. Nonoperating 

The limits of nonoperating shock shall apply to all 
conditions of handling and transportation. This 
includes both isolated devices and integrated 
equipment. 

Equipment subjected to nonrepetitive shock not 
exceeding 32 g at a maximum duration of 10 ms (half 
sinewave) shall not exhibit device damage or 
performance degradation. Shock may be applied in the 
X. Y. or Z axis. 

d. Packaged 

A WREN III drive as packaged by CDC for commercial 
freight shipment shall withstand drop test from 42 
inches (1070 mm) against a concrete floor or 
equivalent. (See Figure 4.) This applies to the 
single unit pack only. 



-22- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 




_ DROP HEIGHT 
42 INCHES 
(1070 mm) 



\\%\\\\\\\\\\\\\\\\\\\\\\\\\\\\w 



7 



^_HHQ£6a_^, FL00R SURFACE 



FIGURE 4. FLAT DROP TEST 



-23- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 

7.4.4.2 Vibration 

a. Operating Normal 

Equipment as installed for normal operation, shall 
comply with the complete specified performance while 
subjected to continuous vibration not exceeding 

5-22 Hz @ 0.010 inches (0.25 mm) displacement 
22-500 Hz @ 0.25 g 

Vibration may be applied in the X. Y. or Z axis. 

b. Operating Abnormal 

Equipment as installed for normal operation, shall 
not incur physical damage while subject to periodic 
vibration not exceeding 

15 minutes duration at major resonant frequency 

5-22 Hz @ 0.010 inches (0.25 mm) displacement 
22-500 HZ @ 0.35 g 

Vibration occurring at these levels may promote 
degraded operational performance during the abnormal 
vibration period. Specified operational performance 
will resume when normal operating vibration levels 
are resumed. This assumes system recovery routines 
are available. Abnormal vibration may be applied in 
the X, Y. or Z axis. 

c. Nonoperating 

The limits of nonoperating vibration shall apply to 

all conditions of handling and transportation. This 

includes both isolated devices and integrated 
equipment. 

Equipment shall not incur physical damage or degraded 
performance as a result of continuous vibration not 
exceeding 

5-22 Hz @ 0.020 inches (0.50 mm) displacement 
22-500 HZ @ 1.00 g 

Vibration may be applied in the X. Y. or Z axis. 

7.4.5 Air Cleanliness 

The WREN III is designed to operate in a typical office 
environment with minimum environmental control. 



-24- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-D 



7.5 



MECHANICAL SPECIFICATIONS 



The following nominal dimensions are exclusive of the 
decorative front panel accessory. Refer to Figure 5 for 
detailed mounting configuration dimensions. 



Height: 
Width: 
Depth: 
Weight: 



3.25 inches 
5.75 inches 
8.0 inches 
7.6 pounds 



82.55 mm 
146.05 mm 
203.2 mm 
3.4 kilograms 



SIDE 



FRONT 




1 


1 , 


. 


1 - irpi 

BOTTOM 


— WJU— 




1 


f 


' 


i 



















-A 



i " 

G 

ho 

■i- l' = 



NOTES: 

1. MOUNTING HOLES. POUR ON BOTTOM. TWO ON EACH 
SIDE. 6-32 UNC. MAX SCREW LENGTH INTO SIDE OF 
CHASSIS 0.31 IN. (7.87 mm). MAX SCREW LENGTH INTO 
BOTTOM OF CHASSIS IS 0.24 IN. (6.1 mm). 

2. FRONT PANEL ACCESSORY 

3. POWER AND INTERFACE CONNECTIONS 



^ - H _ 1 .!!2 a — > 





IN 


mm 


A 


8.0 MAX 


203.2 


B 


5.75 t 0.03 


146 


C 


0.29 ± 0.01 


7.4 


D 


1.87 * 0.02 


47.5 


E 


3.12 ± 0.01 


79.2 


F 


5.88 t 0.01 


149 


G 


3.38 + 0.01 


85.8 


H 


0. 065 ± 0. 02 


1.65 


J 


5.50 t 0.02 


139.7 


K 


0.86 1 0.02 


21.8 


M 


3.25 i 0.04 


82.5 


N 


0.37 REF 


9.4 REF 


P 


0.63 REF 


16 REF 



FIGURE 5. MOUNTING CONFIGURATION DIMENSIONS 



-25- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 



7.5.1 Dcive Orientation 

Only two drive mounting orientations are permitted: disks 
in the horizontal plane and disks in the vertical plane. 
The uppermost surface must be maintained in a level 
position or drive performance may be adversely affected. 
Mounting with either end down (front or tear) is not 
permissible. The drive may not be mounted inverted (upside 
down) in the horizontal orientation. It is recommended foe 
optimum performance that data written in a given 
orientation be read in that same orientation. 

7.5.2 Cooling 

Cabinet cooling must be designed by the customer so that 
the ambient temperature immediately surrounding the WREN 
III will not exceed temperature conditions specified in 
7.4.1. Specific consideration should be given to make sure 
adequate air circulation is present around the circuit 
board at the rear of the drive. 

8.0 MEDIA CHARACTERISTICS 

8.1 MEDIA DESCRIPTION 

The media used in the WREN III has a diameter of 
approximately 5 1/4 inches (130 mm) . The aluminum substrate 
is coated with a thin film magnetic material, and 
lubricated to permit the heads to contact the surface when 
starting and stopping. 

Each data surface has a total of 969 tracks and is capable 
of recording 20,232.720 bytes of unformatted data. 

Media defects are characterized as correctable oc 
uncorrectable depending on the type and magnitude of the 
media flaw. Various error correction codes may be 
implemented. The code chosen should be consistent with 
Control Data media testing and certification methods. WREN 
111 media certification is performed using the following 
standards: 

1. An error burst of 11 bits or less is a correctable 
error. 

2. An error burst greater than 11 bits in length is an 
uncorrectable error. 



-26- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 

8.1 (continued) 

Host systems using the WREN III should have, as a minimum, 
resident capabilities to cecognize and map defective tracks 
and perform track reallocation routines. 

At the time of shipment from the point of manufacture, the 
WREN 111 recording surfaces will meet the following 
requirements. 

1. 969 total tracks per surface. 

2. Track to be error free on each data surface. 

3. 30 defects per surface maximum. 

4. Cumulative defects not to exceed 1 per megabyte, 
based on total available drive capacity. 

9.0 DEFECT AND ERROR MANAGEMENT 

The WREN III. as delivered, complies with this 
specification. The read error rate .and specified storage 
capacity are not dependent upon use of defect . management 
routines. However, a carefully chosen defect management 
plan can significantly enhance overall system performance. 

Identified defects are recorded on the defects list tracks 
per CDC ESDI specification (Sections 5.5 and 6.5). It is 
recommended that these known defects be reallocated during 
the initial format operation. Sector reallocation is 
suggested because, in general, it is more efficient and may 
offer significant performance improvement. Error Correction 
Code (ECC) should be used to correct additional flaws as 
they occur. ECC is recommended since most of the defects 
are recoverable with ECC. If ECC is not used, defects are 
usually unrecoverable and need to be reallocated as they 
are discovered. 



-27- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-3 

10.0 INTERFACE CABLING REQUIREMENTS /OPT IONS 

10.1 RADIAL CONFIGURATION 

Interface cabling options foe the WREN III are shown in 
Figure 6. View A of Figure 6 shows each drive interfaced to 
its own control cable, which allows interfacing an 
arbitrary number of drives and a variety of system 
operational techniques. Each drive has its data cable and 
control cable connected to the host controller. The length 
of each individual cable must not exceed 10 feet (3.0 
metres). Terminator resistors must be installed in the host 
controller for each data cable and for each control cable. 
For this configuration, a terminator resistor pack must be 
installed in each WREN III Disk Drive. The orientation of 
Pin 1 of the terminator resistor does not matter. Either 
way is correct. 

10.2 DAISYCHAIN CONFIGURATION 

A daisychain configuration connects a maximum of seven 
drives in parallel on a common control cable. (See 
paragraph 11.1.1). Only the drive selected by the host 
system has its control signals enabled through this common 
interface. View B of Figure 6 illustrates a daisychain of 
WREN III Disk Drives or other ESDI devices. A terminator 
resistor pack is required in the host controller for each 
data cable. Only the last ESDI device in the daisychain 
cequires a terminator resistor pack for the control cable. 
Terminator resistor packs for the control cable of other 
drives must be removed. See Figure 7 for location of the 
terminator pack. The total combined control cable length 
(from the controller to the first drive, to the second and 
subsequent drives) must be not more than 10 feet (3.0 
metres) . 

Refer to paragraph 11.1.1 for logical drive selection. 



-28- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 



DATA 



CONTROL OATA 



HOST CONTROLLER 



CONTROL DATA 



CONTROL OATA 



CONTROL 



-_ _ _ _-j --j _ 



WREN 



a Pn P\ H 

EDI B EJ 



WREN 



&— a 



w 



WREN 



&— © 



WREN 



EACH CONTROL CABLE LENGTH 
MUST NOT EXCEED 10 FEET 
(3.0 m). EACH DATA CABLE 
LENGTH MUST NOT EXCEED 10 
FEET (3.3 <n). 



VIEW A 



HOST CONTROLLER 



DATA 



CONTROL DATA 

"""0 — cr 



a 



DATA 



&*E 



CONTROL 



CONTROL 



WREN OR OTHER 
ESDI DEVICE 



u 



^M 



TOTAL CONTROL CABLE LENGTH 
MUST NOT EXCEED 10 FEET 
(3.0 m). EACH DATA CA8LE 
LENGTH MUST NOT EXCEED 10 
FEET (3.0*). 



WREN OR OTHER 
ESDI DEVICE 



WREN OR OTHER 
ESDI DEVICE 



VIEW B 

*T INDICATES REMOVEABLE TERMINATOR RESISTOR PACK 

, ^ WREN DATA PORTS ARE PERMANENTLY TERMINATED. 

(, HH057a j 

**MAY BE UP TO SEVEN (7) OEVICES IN DAISYCHAIN. 



FIGURE 6. INTERFACE CABLING OPTIONS 



10.3 



DC CABLE AND CONNECTOR 



The WREN III receives DC powec through a 4 pin eight angle 
connectoc (see Table 2 foe pin assignment) mounted on the 
secvo circuit board (see Figure 7). Recommended part 
numbers of the mating connector are provided, but 
equivalent parts may be used (See Table 3). 



-29- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 



TABLE 2. DC INTERFACE 



POWER 


LINE DESIGNATION 1 




+12 V | 




+12 v Return j 




+5 V Return | 




+5 V 1 



PIN NUMBER 1 


J2- 


-01 i 


J2- 


-02 | 


J2- 


-03 | 


J2- 


-04 I 



TABLE 3. EQUIVALENT PARTS 



TYPE OF CABLE 
18 AWG 



CONNECTOR 



AMP 1-480424-0 



1 CONTACTS (20-14 AWG) 
| AMP 60619-4(Loose Piece) 
I AMP 61117-4 (Strip) 



10.4 DATA CABLE AND CONNECTOR 

The I/O connector for the data interface is a 20 pin board 
edge connector (Figure 8 and 9a). The odd pins are located 
on the noncomponent side of the printed circuit board. The 
even pins are on the component side of the printed circuit 
board. A Key slot is provided between pins 3 and 5. CDC 
recommends keying this connector to prevent installing it 
upside down. However, the ViREN will not be damaged if the 
connector is installed upside down. 



-30- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77 7 3 82 12 -B 



10.4 



(continued) 



Recommended part numbers foe the mating connector are 
included below, but equivalent parts may be used. 



CONNECTOR (20 PIN) 
3M-3461-0001 
AMP 88373-6 



CABLE 

Flat Cable (Stranded AWG 28) 3M-3365-20 

Flat Cable (Stranded AUG 28) 3M-3517-20 (Shielded Cable) 



KEY 

AMP 583274-1 
3M-3439-0000 



DRIVE SELECT 

JUMPER 

CONFIGURATIONS 



* * rti tfi r. 



1 1-' ••• . 
n 1 1 
ii ii i 

Zl L.J L.J L.J L.J L.J L.J 



• !••!•!! 



^ HH004a ; 





ORIVE SELECT 1 
DRIVE SELECT 2 
DRIVE SELECT 3 

ORIVE SELECT 4 
ORIVE SELECT 5 
ORIVE SELECT 6 

DRIVE SELECT 7 



MOT« 

UNIT SELECT ZERO (NO JUMPER) IS INVALID (• 



1 

2 
3 

4 


POWER 


+12 V 
+12 V RET 
+ 5 V RET 
+ 5 V 



OC POWER CONNECTOR 



The position of this jumper when drive is shipped is 
determined by a customer configuration document. 

FIGURE 7. 1/0 CONNECTION 



-31- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-? 



-'.EYING NOTCH 
1 BETWEEN PIN 3 i 5) 



PIN 33 




CONTROL CABLE 



OATA CABLE 



DATA 30AR0 
:3MP0.N6NTS sown 



i^rFZJ^; 



FIGURE 8. CABLE CONNECTION 



NON-COMPONENT SIDE 



30ARD , 

THICKNESS) 

0.362 ± 0.005 



0.065 



ir 



.0335 ♦ .0030 
- .0010 



19 



0.050 

0.100 



0.450 



3 1 

/■N 



KEYING SLOT 



J 



J u 



PIN 

T 

.41 

1 



0.400 



0.350 



1.080 : 0.005 



CsuO 



FIGURE 9a. DATA CABLE INTERFACE 



-32- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 



10.5 CONTROL CABLE AND CONNECTOR 

The I/O connector foe the control interface is a 34 pin 
board edge connector. The odd pins are located on the 
component side of the printed circuit board and are 
connected to the ground plane. The even pins are on the 
noncomponent side of the printed circuit board. A key slot 
is provided between pins 3 and 5. (See Figure 8 and 9b.) 
CDC recommends keying this connector to prevent installing 
it upside down. However, the WREN will not be damaged if 
the connector is installed upside down. 

Recommended part numbers for the mating connector are 
provided, but equivalent parts may be used. 

CONNECTOR (34 PIN) 

3M-3463-0001 

AMP 88373-3 

KEY 

AMP 583274-1 

3M-3439-0000 

CABLE 

Flat Cable (Stranded AWG 28) 3M-3365-34 

Flat Cable (Stranded AWG 28) 3M-3517-34 (Shielded Cable) 

Spectra Strip Twist' n Flat 455-248-34 (Stranded AWG 28 

Twisted Pair) 

10.6 INTERFACE DRIVERS /RECEIVERS 

The WREN III uses two types of signals; single ended and 
balanced differential. The data and clock signals use 
balanced differential drivers and receivers. All other 
signals use single ended drivers and receivers. 

10.6.1 Single Ended Drivers/Receivers 

10.6.1.1 Transmitter Characteristics 

The WREN III uses the 7406 open collector hex inverter 
buffer/driver to transmit status to the host. This driver 
is capable of sinking a current of 40 mA with a low level 
output voltage of 0.7 V. (See Figure 10). 



-33- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77733212-F 

10.6.1.2 Receiver Characteristics 

The WREN III uses the 74LS14 Hex Inverter with hysteresis 
gate as a line receiver. The input of each receiver is 
terminated in a 150 ohm pullup resistor as shown in Figure 
10. 



0.050 



0.100 



•0.365 



33 
/~\ f"\ r\ 






I 



SERVO PWA 
COMPONENT SIDE 



ir 



.0335 * .0030 
- .0010 



0.450 



KEYING SLOT 

0.050 



3 1 



A\- 



.1.780 z 0.005. 



PIN 
T 

I 
0.400 



NOTE: TOLERANCE ±0.010 in. EXCEPT WHERE OTHERWISE NOTED. 



(jU46b_) 



FIGURE 9b. CONTROL CABLE INTERFACE 



-34- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 



LINE DRIVER 



LINE RECEIVER 



TRANSMITTER 




FLAT CABLE PAIR 



■<* 



10 FEET (3 m) MAX. 



1/6 7406 




A PART OF REMOVABLE RESISTOR PACK. (SEE FIGURE 9.) 

INTERFACE SIGNALS LEVELS AND LOGICAL SENSE AT THE WREN I/O CONNECTOR ARE DEFINED AS FOLLOWS: 



LOGIC LEVEL 



DRIVER OUTPUT 



RECEIVER INPUT 

HIGH (NEGATED) (0) >2.5 V; <5.25 V >2.0 V; <5.25 V 

LOW (ASSERTED) (1) <0.7 V; >0.0 V <3.8 V:>0.0 V 

THE DIFFERENCE IN THE VOLTAGES BETWEEN INPUT AND OUTPUT SIGNALS IS DUE TO THE LOSSES IN "HE CABLE 



CjlH057b j 



FIGURE 10. SINGLE ENDED TRANSMITTERS AND RECEIVERS 

10.6.1.3 Terminator Characteristics 

The terminator is a resistor module that plugs into a 
socket in the last drive in a daisychain as shown in Figure 
7. Each drive is furnished with a terminator. Terminators 
must be removed from all except the last drive on the cable 
prior to daisychain operation. (See Figure 6.) An 
equivalent terminator must be provided in the controller on 
each input signal line from the drive to the controller. 
Only the Control cable resistor module is removable. 



-35- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 

10.6.2 Balanced Differential Drivers/Receivers 

10.6.2.1 Transmitter Characteristics 

The WREN III uses 26LS31 type balanced differential 
drivers. An assertion on the interface is defined when the 
» + » output is more positive than the "-" output. (See 
Figure 11.) 

10.6.2.2 Receiver Characteristics 

The WREN III uses 26LS32 type balanced differential 
receivers terminated per Figure 11. An assertion on the 
interface is defined when the " + " input is more positive 
than the "-" input. (See Figure 11.) 

10.6.2.3 Terminator Requirements 

Each differential receiver in the drive is terminated with 
a 100 ohm resistor. (See Figure 11.) An equivalant 
terminator must be provided in the controller on each input 
signal line from the drive to the controller. 



TRANSMITTER 



26LS31 



A 



^ 



■» 



<ih-» 



BALANCED 
TRANSMITTER 



A 



10 FT. (3.0 m) 
MAX. 



-» 



■»> 



-»-fr 



A 



100 Q 



RECEIVER 



26LS32 



SAIANCED 
RECEIVER 



A CA8LE SH *U- ** PL* 1 CABLE 3M-3365-20 OR EQUIVALENT 

A TERMINATOR RES I SI 
MUST 3E RAOIALLY 

A, NOMINAL '•-' LINE OV 



^ TERMINATOR RESISTORS ARE LOCATED AT ALL RECEIVER INPUTS. THESE SIGNALS 
MUST 3E RAOIALLY CABLED. 



NOMINAL "♦" LINE 
HH00?a~~ 



~ l — \y — * 

NEGATION X **$& 



ASSERTION 



v. ™ — Z-J 

FIGURE 11. BALANCED DIFFERENTIAL DRIVERS /RECEIVERS 



-36- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 



10.7 



SIGNAL/ CHASSIS GROUNDS 



The WREN III Disk Drives ace manufactured with the signal 
and chassis grounds common. Zero ohm resistors (designated 
W3 and W4) on the Data board allows modification of this 
relationship at the customer's option. The results of 
connecting/disconnecting the zero ohm resistors are listed 
in Table 3A. The customer can select any of these grounding 
options by removing W3 and/or W4. A customer configurator 
document specifies which of the Table 3A configurations a 
drive will have when shipped. 

TABLE 3A 



W4 1 W3 1 RESULT 


X | X | Grounds common, quick connect terminal tied 
1 I to common around (as manufactured) . 


X | 1 Grounds separate, quick connect terminal tied 
I 1 to chassis around. 


| X | Grounds separate, quick connect terminal tied 
1 1 to sianal around. 


| 1 Grounds separate, quick connect terminal 
1 1 floatina. 



X * Connected 

a Not Connected 



See Figure lib for physical locations of W3 and W4 and Figure 11a 
for schematic. 



W4 

JUMPER 



QUICK CONNECT 
TERMINAL 



W3 



JUMPER 



/777 

CHASSIS 
GROUND 



D.C. RETURNS 



SIGNAL 
GROUNO 



C JU 2 ZiO 



FIGURE 11a. SCHEMATIC DIAGRAM OF W3 AND W4 



-37- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-C 




_!£ J 5 U 



w 



H^IF* 



*z - c:nnects X 3R0UN0 «0 AC ground *asrwEs 

<H - XNNEC7S AC 5P.0UNO 70 T<£ 3RI7E CASSIS 
;u3 ANO '<* ARE IER0 OH* BESIST5RS: 



i -.ms u r ) 



FIGURE lib. ESDI DATA PWA SHOWING W4 



QUICK CONNECT TERMINAL 



TERMINATOR 
RESISTOR 



CONTROL CA31E CONN 



OATA CABLE CONN 



z 




V JL 22 1 C _• 



OATA 30ARD 



44 



FIGURE lie. LOCATION OF W3 AND W4 



-38- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 



11.0 SERIAL MODE INTERFACE SIGNAL DESCRIPTION 

This Section (11) specifies standard WREN III ESDI 
parameters for the SERIAL mode of operation. Section 5.0 of 
the ESDI Specification (77738076) contains a detailed 
description of the SERIAL mode and must be referenced to 
define the ESDI interface operation. 

Figures 9 and 10 of the ESDI Specification lists the 
signals between the drive and the controller for the SERIAL 
mode of operation. These same signals are used by the 
standard model 94166 WREN III. WREN III does not support 
the ESDI step mode of operation. 

11.1 CONTROL INPUT LINES 
11.1.1 Drive Select 

Refer to ESDI Specification Section 5.1.1. 

The following characteristics apply to the DRIVE SELECT 
lines: 

1. Logical unit designation for up to 7 drives is 
performed during installation by installing the 
jumper on the baseboard assembly as shown in Figures 
7 and 12 of this specification. 

2. The controller shall not attempt to select the drive 
until 1 second after DC power is applied. The READY 
output will be valid (whether asserted or negated) 
within 1 us after the drive is selected. Refer to 
Fig. 13. 

3. The drive will be selected (and the DRIVE SELECTED 
Signal asserted) within 1 us after the DRIVE SELECT 
lines contain that unit's select address. The drive 
will be deselected (and the DRIVE SELECTED signal 
negated) within 1 us after the DRIVE SELECT lines 
contain another unit's select address. 

4. The DRIVE SELECT lines must remain asserted for 1 us 
after a write operation. 

5. When the DRIVE SELECT lines are asserted, a head 
change will occur per Section 11.1.2 requiring a 
delay before a cead or write operation can be 
initiated. Refer to Figure 12. 



-39- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-C 



11.1.1 (continued) 

Install the drive select jumper for the desired logical 
unit address. Refer to Figure 7 foe location of unit select 
header. The logical address is selected by installing the 
select jumper in the Drive Select header as shown in Figure 
7. 



DC POWER 





H 


1 SEC MIN L_ 
AFTER DC 1 






DRIVE 
SELECT 




1 




1 


— •{ [-*— t^. 1 


.us 


—•J m t < 1 jiS 


SELECTED 

I 




1 


1 "" 

1 


nfJ TVF 






— hJ L— t< i JJS 


READY U 


1 


ASSERTED 


i 


1 




35 SEC MAX 




1 



(\4HQ03c ; 

FIGURE 12. POWER TURN ON AND DRIVE SELECTION 

11.1.2 Head Select 2(0). 2(1), 2(2). and 2(3) 

Refer to ESDI Specification Section 5.1.2. 

These lines select the proper media and head for data 
transfer. See Table 4. 

Head selection may be changed at any time following 
assertion of DRIVE SELECT, but must occur a minimum of 5 us 
prior to a write operation. WRITE GATE must be negated a 
minimum of 1 us prior to a head change. READ DATA will be 
valid within 10 ns from a head selection (change) if the 
drive is selected. READ GATE is asserted, the DRIVE READY 
line is asserted, the COMMAND COMPLETE line is asserted, 
and a PLO Sync field is present. 

Neither the DRIVE READY line or the COMMAND COMPLETE line 
will change as a result of a head selection (change). 



-40- 



PRODUCT SPECIFICATION FOE WREN III DISK DRIVE MODEL 94166 77738212-C 



CO 


STROLLER 




FLAT RIBBON OR 

TWISTED PAIR (J METRES MAX) 






DRIVE 












, 








HEAD SELECT 2(3) 


2 




i 


' 






HEAD SELECT 2(2) 




» 








-WRITE GATE 


« 




' 




-CONFIC/ -STATUS DATA 


S 




* 






-TRANSFER ACK 




10 






f 




-ATTENTION 




12 
















-MEAD SELECT 2(0) 




1* 














-SECTOR /-ADDRESS MARK POUND 


It 








1 




-HEAD SELECT 2(1) 




IS 


.- , '• m 




f 




-INDEX 


20 






* 


, 




REAOY 


22 














-TRANSFER REQ 




2« 






T 

1 




DRIVE SELECT 2(0) 




26 












DRIVE SELECT 2(1) 




28 












DRIVE SELECT 2(2) 




JO 








i 




REAO CATE 




32 






J. 


-COMMAND DATA 


3« 















> COWHAND CABLE 



^ iiito£aid__> 



CONTROLLER 


FLAT RIBBON OR 

TWISTED PAIR (1 METRES MAX) 






ORIVE 






4 -ORIVE SELECTED 




I 

2 
3 

» 




-SECTOR /-ADDRESS MARK FOUND 


-COMMANO COMPLETE 


-AODRESS MARK ENABLE 






















-WRITE CLOCK 




7 
1 








-WRITE CLOCK 




•REAO /REFERENCE CLOCK 


10 

11 




-READ /REFERENCE CLOCK 






\ 


-NRZ WRITE DATA 




13 

1» 




! 


-NRZ WRITE DATA 










f 






_ 




•NRZ READ DATA 


17 
It 




_ -NRZ REAO DATA 






-INOEX 


20 















y DATA CABLE 



O-L 5iO 



FIGURE 12a. ESDI INTERFACE PINOUTS 



-41- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77733212-C 



11.1.2 



(continued) 



TABLE 4. HEAD SELECT ENCODING 



OISK 
NOMENCLATURE 



HEAO 

SELECT 



,1 2 o 





1 








TOP OR 5th DISK 


1 


1 




4th OISK 


o : 


1 







3 1 


<j 


- 


3rd DISK 


'2-1. 


_Q_ 


JL— 







1 


1 


2nd DISK 





I 






TOP OF SPINDLE 



HEAD NUMBER 
BY MODEL CAPACITY 
IN MEGABYTES 



A))))))))}))))))), 



132 



141 101 



>}>)>W>>))>>))))))>>))>>>))\--% 



- m»))))))»)?»}w)}») ))m))))M>}»)}>7 7u i 



IMMittttMifitti/it//Itft/IMtff/tMtM/fMH* 



Ui/f///t///t////tiiiH//J///fti//ift//f//MI//it 



BOTTOM OR 1st OISK 



Hrr—- * 7 ^^^^^^ 



HEAO SELECTS OTHER 
THAN THOSE SHOWN 
ARE INVALID 



I 



BASE DECK 



7- 



INVALID HEAO 



11.1.3 Write Gate 

Refer to ESDI Specification Section 5.1.3. 

11.1.4 Read Gate 

Refer to ESDI Specification Section 5.1.4. 

11.1.5 Command Data 

Refer to ESDI Specification Section 5.1.5. (Figure 12a) 

The WREN HI responds with TRANSFER ACX in typically 2 us 
from either edge of TRANSFER REQ. This promotes signifi- 
cantly improved performance ovec the allowed 10 ms and 
should be recognized. 

11.1.5.1 Command Data Bits 15 thru 12 Decode Definition 

Refer to ESDI Specification Section 5.1.5.1. 

The 94166 WREN III implementation of the ESDI command set 
is summarized in the following table. Any ESDI command not 
implemented will be treated as an Invalid Command. A 
command transfer attempt to the drive should not be 
initiated until the COMMAND COMPLETE line from the dcive is 
asserted just befoce the transfer. 



-42- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-C 

11.1.5.1 (continued) 

SERIAL MODE COMMAND SET IMPLEMENTED WREN III 

• SEEK YES 

• RECALIBRATE YES 

• REQUEST STATUS 

-STANDARD YES 

-VENDOR UNIQUE YES 

• REQUEST CONFIGURATION YES 

• SELECT HEAD GROUP NO 

• CONTROL 

-RESET ATTENTION AND STANDARD 
STATUS 0-11 YES 

-STOP MOTOR NO 

-START MOTOR YES 

• DATA STROBE OFFSET - 3 LEVELS/ 

ONE PHYSICAL OFFSET YES 

• TRACK OFFSET - 3 LEVELS/ 

THREE PHYSICAL OFFSETS YES 

• INITIATE DIAGNOSTICS YES 

• SET BYTES PER SECTOR YES 

• SET CONFIGURATION YES 

The following ESDI commands are recognized by the Model 
94166 WREN III. Additional information not contained in the 
ESDI specification is included. 

SEEK (0000): 

The SEEK times defined in Section 5.0 of this specification 
are measured from the time the last bit of the command word 
is received by the drive. The COMMAND COMPLETE signal line 
will be asserted when the drive has completed the SEEK 
operation and is ready to accept the next command word. 



-43- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 

11.1.5.1 (continued) 

RECALIBRATE (00011 t 

The maximum time to complete the Recalibrate function is 
100 milliseconds, and is measured from the time the last 
bit of the command word is received by the drive. The 
COMMAND COMPLETE signal line will be asserted when the 
Recalibrate function is completed. 

REQUEST STATUS (0010): 

I. REQUEST STANDARD STATUS (command modifier equals 0000) 

The controller need only request standard status in 
response to the drive's assertion of the ATTENTION 
line. 

The controller asserts the COMMAND COMPLETE line 
after it has read the drive's standard status wocd. 

The controller should always first request the 
Standard Status in response to the assertion of the 
ATTENTION line. The "Vendor Unique Status Available" 
bit in the Standard Status Word defines whether or 
not the Vendor Unique status words are valid. 

See Section 11.2.3.2 for the response to the "Request 
Status" Command. 

II. REQUEST VENDOR UNIQUE STATUS (command modifiers 0001 
through 1111) 

The Vendor Unique Status consists of up to 15 unique 
words of status and is valid only if bit 2 of the 
Standard Status is a one. 

This status is only intended to be used by trained 
field maintenance personnel and is not intended to be 
interpreted by disk controllers or operating systems. 
If this bit is detected the controller should attempt 
to reset Standard Status and reattempt the ociginal 
function a minimum of three times prior to defining 
the drive as inoperative. After the last attempt the 
Vendor Unique Status words should be read by the 
controller and sent back to the system for a print 
out of these codes which may then be used by the 
field maintenance personnel. 



-44- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-C 

11.1.5.1 (continued) 

REQUEST CONFIGURATION (0011): 

Configuration data is sent to the controller via the 
CONFIG-STATUS line as a result of receiving a "Request 
Configuration" command. The exact Configuration Word sent 
is dependent upon the Configuration Word requested by the 
controller via the Command Modifier Bits. (See Table 5.) 

See Section 11.2.3.1 for the responses to the "Request 
Configuration" commands listed in Table 5. 



CAUTION 

Configuration status cannot bo requested until COMMAND 
COMPLETE is asserted. This occurs 35 seconds after the 
beginning of power up. 



TABLE 5. SUMMARY OF CONFIGURATION INFORMATION REQUESTED 



COMMAND MODIFIER 

BITS 
11 10 9 8 



1 

10 

11 

10 

10 1 

110 
111 
10 
10 1 

10 10 
10 11 
110 
110 1 
1110 

1111 



CONFIGURATION INFORMATIION REQUESTED 

GENERAL CONFIGURATION OF DRIVE AND 
FORMAT (See Table 6) 

NUMBER OF CYLINDERS FIXED 

NUMBER OF CYLINDERS REMOVABLE 

NUMBER OF HEADS 

MINIMUM UNFORMATTED BYTES PER TRACK 

UNFORMATTED BYTES PER SECTOR (HARD 

SECTOR ONLY) 

SECTORS PER TRACK (HARD SECTOR ONLY) 
MINIMUM BYTES IN ISG FIELD 
MINIMUM BYTES PER PLO SYNC FIELD 
NUMBER OF WORDS OF VENDOR UNIQUE 
STATUS AVAILABLE 

INVALID CONFIGURATION REQUEST CODES 

VENDOR INDENT1FICAT10N 



-45- 



PRODUCT SPECIFICATION FOR ViREN III DISK DRIVE MODEL 94166 77738212-C 

11.1.5.1 (continued) 

CONTROL (0101): 

Refec to ESDI Specification Section 5.1.5.1. 

The WREN III will implement the following Control Commands 
(as specified by the Command Modifier Bits). Any Command 
Modifier received which is not listed will be treated as an 
Invalid Command. 

a. Reset Interface Attention and Standard Status bits 
(Command Modifier 0000) 

This command must be sent to ceset the interface 
ATTENTION line and the Standard Status Bits (0-11). This 
command should not be sent until the controller has read 
the Standard Status Word to determine what caused the 
ATTENTION line to be asserted. 

b. Start Motor (Command Modifier 0011) 

This command must be sent by the controller to turn on 
the spindle motor when the "Motor Control Option 
Implemented" General Configuration bit is asserted (see 
Sections 11.2.3.1 and 12). This command is not required 
to turn on the spindle motor if the "Motor Control 
Option Implemented" configuration bic is negated, and 
will be treated as an Invalid Command. 

The interface COMMAND COMPLETE line will be asserted 
when the Control Command has been executed. 

NOTE 
If the "Motor Start" option is implemented (see Section 
12.1), only the following five commands are recognized as 
valid before the Motor Start command is issued (i.e., while 
the "Spindle Motor Stopped" bit is set in the Standard 
Status word - see Section 11.2.3.2). 

COMMAND CODE 

COMMAND (Bits 15-0) 

Request Standard Status 2000H 

Request Vendor Unique Status 2100H - 2F00H 
Request General Configuration 3000H 
Reset Interface Attention 5000H 

Start Spindle Motor 53QOH 

Any other commands will cause "ATTENTION" to be asserted 
and an "INVALID COMMAND" status returned. 

DATA STROBE OFFSET (0110): The drive will accept all of the 
Data Strobe Offset Commands but will only offset from 
nominal by a single amount. 

-46- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-C 

11.1.5.1 (continued) 

TRACK OFFSET (0111): -The drive will accept all of the Track 
Offset Commands and can execute three physical offset levels. 
This command may require up to 3 milliseconds for command 
execution after the command word has been received. 

INITIATE DIAGNOSTICS ( 1000 ) : -The drive will accept this 
command. If an error state exists in the dcive, the ATTENTION 
signal will be asserted when the COMMAND COMPLETE signal is 
asserted to signify that status is available. 

If no error state exists in the drive, the COMMAND COMPLETE 
signal will be asserted and the ATTENTION signal will not be 
asserted. 

SET UNFORMATTED BYTES PER SECTOR (1001): -All zeros in bits 
through 11 is an invalid parameter. The maximum value in bits 
thru 11 is 4.095 (decimal). The minimum value is 82 
(decimal) . 

COMMAND DATA CODES 1010 THROUGH 1101 AND 1111: -These codes are 
invalid Command codes. 

Codes 1010. 1011. 1100. 1101 AND 1111 are reserved for use by 
the WREN III. If these commands are used by the Controller, 
the interface ATTENTION line will be asserted and an Invalid 
Command Standard Status bit will be asserted. 

SET CONFIGURATION (1110) 

This command provides a soft switch capability such that the 
controller can override the soft sector/hard sector option 
switches SW-2, SW-3. and SW-4 (paragraph 12.1). After power 
down/power up. the configuration reverts to that specified by 
the "hard" option switches. The controller can then change the 
setting with the Set Configuration command. Command focmat is 
shown below. 

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 P 

CMD FUNCTION | SOFT SWITCH NO. | SOFT SWITCH PARAMETER 
| j 

1 1 1 0|0 0011 xxxx xxOl * Set Soft Sector 

I xxxx xxlO « Set Hard Sector 



-47- 



PRODUCT SPECIFICATION FOE WREN III DISK DRIVE MODEL 94166 



'7733212-C 



11.1.6 Transfer Request 

Refer to ESDI Specification Section 5.1.6. 

11.1.7 Address Marie Enable 

Refer to ESDI Specification Section 5.1.7 and Section 
11.1.3 of this document. 

NOTE: In the fixed sector mode, ADDRESS MARK ENABLE does not 

cause an ADDRESS MARK to be written on the media. The 

trailing edge of ADDRESS MARK ENABLE with WRITE GATE 

asserted initiates the writing of the header PLO sync field. 

11.2 CONTROL OUTPUT LINES 

11.2.1 Drive Selected 

Refer to ESDI Specification Section 5.2.1. and Section 
11.1.1 of this specification. 

11.2.2 Ready 

Refer to ESDI Specification Section 5.2.2. 

11.2.3 Conf ig/Status Data 

11.2.3.1 Configuration Response Bits 

In response to the "Request Configuration" command (see 
Section 11.1.5.1) 16 bits of configuration information is 
returned to the controller. The Command Modifier bit code 
(Bits 11-8) selects the specific configuration information 
to be returned. 



COMMAND 
MODIFIER 
BITS (11-8) 
0000 



CONFIGURATION STATUS 



General configuration status information 
shown in Table 6 is returned. 



-48- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 9416 6 777 3 8 212-C 

11.2.3.1 (continued) 

TABLE 6. DRIVE GENERAL CONFIGURATION STATUS 



CONFIGURATION 
3IT 


FUNCTION 


WREN 

III 

VALUE 


15 


NOT A MAGNETIC DISK DRIVE 







14 


FORMAT SPEED TOLERANCE GAP REQUIRED 





A 


13 


TRACK OFFSET OPTION AVAILABLE 


1 




12 


DATA STROBE OFFSET OPTION AVAILABLE 


1 




il 


ROTATIONAL SPEED TOLERANCE !S > O.S 







10 


TRANSFER RATE > 10 MHz 







9 


TRANSFER RATE > 5 MHz < 10 MHz 


1 


A 


5 


TRANSFER RATE £ 5 MHz 







; 


REMOVABLE CARTRIDGE DRIVE 


c 




= 


FIXED DRIVE 


1 




5 


MOTOR CONTROL OPTION IMPLEMENTED 


1 OR 


A 


4 
3 


HEAD SWITCH TIME > 15 ps 
NOT MFH 





A 
A 


1 


CONTROLLER SOFT SECTORED (AOR MARK) 


OR 11 


-A 


■ 


DRIVE HARD SECTORED (SECTOR PULSES) 


10H, 





CONTROLLER HARD SECTORED (BYTE CLK) 








A 

A 
A 

A 



THE ZERO INOICATES THAT NO SPEED TOLERANCE GAPS ARE REQUIRED 
(EITHER BETWEEN SECTORS OR AT THE ENO OF A TRACK) IN THE 
WREN FORMAT. 

SEE SECTION 5.0 OF THIS SPECIFICATION FOR EXACT VALUE. 

THE ZERO INOICATES THAT THE HEAO SWITCH TIME IS LESS THAN 
15 MICROSECONDS AND THAT THE CCMMANO COMPLETE LINE WILL NOT 
BE NEGATED WHEN A HEAD CHANGE IS PERFORMED BY THE DRIVE. 

THE APPROPRIATE BIT WILL BE ASSERTED TO INDICATE THAT THE SIGNAL 
WHICH IS CURRENTLY BEING TRANSMITTED ON THE SECTOR/ADDRESS MARK 
c OUNO SIGNAL LINES IN THE INTERFACE. THESE ARE SWITCH SELECTABLE 
(SEE SECTION 12.0). 

INTERNAL RECORDING MECHANISM IS RLL. DRIVE ?ECJIRES ZEROS 
FOR "HE =L0 SYNC "IELD. 

SWITCH SELECTABLE (SEE SECTION 12;. 



(_H£37a 



-49- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-D 
11.2.3.1 (continued) 



COMMAND 
MODIFIER 
BITS (11-8) 
0001 



0010 



0011 



0100 



0101 



0110 



0111 



1000 



1001 



1010 
thru 
1110 

1111 



CONFIGURATION STATUS 



Number of Cylinders. FIXED - Value returned 
equals the maximum number of drive cylinders. 

Number of Cylinders. REMOVABLE - Value 
returned is to signify no removable media. 

Number of Heads - Value returned in bits 
15-8 is to signify no removable media is 
present. 

Value returned in bits 7-0 (in decimal) is 
either 5. 7 or 9 and is determined by the 
number of R/W heads installed (i.e.. model 
number) . 



Minimum Unformatted Bytes per 
returned is 20.880 (decimal). 



Tracfc. Value 



Unformatted Bytes per Sector. The Value will 
be the Integer value of 20,880 (decimal) 
divided by the number of Sectors per Tracic 
(see following command modifier code 0110). 

Sectors per Tracfc. The default value is 
determined by switch settings at the time of 
installation (see Section 12.0). The Default 
value may be overridden by the Set Bytes per 
Sector command. See also "Set Bytes per 
Sector" command which results in a value of 
integer 20.880 divided by desired number of 
bytes per sector. 



Minimum Bytes in ISG Field 
Value returned in bits 1S-8 
Value returned in bits 7-0: 



12 (decimal) 
16 (decimal) 



Minimum Bytes per PLO Sync Field 

Value returned in bits 15-8: 

Value returned in bits 3-0: 11 (decimal) 

Maximum number of vendor unique status words 
available. Value returned is 15 (decimal). 

Invalid command modifier codes when part of 
"REQUEST CONFIGURATION" command. 



Vendor Identification. 



-50- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-C 

11.2.3.2 Status Response Bits 

In response to the "Request Status" command (see Section 

11.1.5.1) 16 bits of status information is returned to the 
controller. 

The WREN III will support the following standard status 
bits as referenced in the ESDI Specification Section 
5.2.3.2. 

SERIAL MODE STANDARD STATUS BITS SUPPORTED WREN III 

Bit(s) Function 

15, 11. 10 RESERVED AND WILL BE ZERO YES 

14 REMOVABLE MEDIA NOT PRESENT NA (=0) 

13 WRITE PROTECTED. REMOVABLE 

MEDIA NO (*0) 

12 WRITE PROTECTED. FIXED 

MEDIA NO (=0) 

9 SPINDLE MOTOR STOPPED YES 

8 POWER ON RESET CONDITIONS 

EXIST YES 

7 COMMAND DATA PARITY FAULT YES 

6 INTERFACE FAULT YES 

5 INVALID OR UN IMPLEMENTED 

COMMAND FAULT YES 

4 SEEK FAULT YES 

3 WRITE GATE WITH TRACK 

OFFSET FAULT YES 

2 VENDOR UNIQUE STATUS 

AVAILABLE YES 

1 WRITE FAULT YES 

REMOVABLE MEDIA CHANGED NA (=0) 



-51- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-C 



11.2.3.2 (continued) 

The individual standard status bit definitions ace defined 
as follows: 

a. Reserved - (Bits 15, 11. and 10) 

These bits are reserved and will be zero. 

b. Removable Media Not Present (Bit 14) 

This bit will always be a for the WREN III drive. 
The WREN Drive contains only fixed media. 

c. Write Protected. Removable Media (Bit 13) 

This bit will always be zero for the WREN III drives. 

d. Write Protected. Fixed Media (Bit 12) 

This bit will always be zero for the WREN 111 drives. 

e. Spindle Motor Stopped (Bit 9) 

This bit is asserted when the spindle motoc is 
stopped. (See also Section 12.) 

f . Power On Reset Conditions Exist (Bit 8) 

This bit is asserted after a Power On Reset occurs or 
when an internal drive fault condition occurs which 
would cause an internal Power On Reset operation to 
occur (e.g.. a momentary loss of a DC voltage, etc). 
This bit is intended to notify the controller that 
the drive has reinitialized itself for the default 
drive characteristics (e.g.. default Number of Bytes 
Per Sector, etc.). The controller should read the 
configuration words to determine if the default drive 
characteristics are the desired operating conditions 
and/or send the required commands to the drive to set 
up the desired drive operating conditions. (See also 
Section 12 if the "Spindle Motor Control Option 
Implemented" is selected.) 

g. Command Data Parity Fault (Bit 7) 

This bit will be asserted when a parity error is 
detected on the Serial Command Data received from the 
controller. The drive will not attempt execution of a 
command if a parity error is detected. The controller 
should reset the Standard Status and attempt to send 
the original command to the drive at least 3 times 
prior to defining the drive as inoperable. 



-52- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-C 



11.2.3.2 (continued) 

h. Interface Fault (Bit 6) 

This bit will be asserted when an interface protocol 
violation is detected by the drive. This bit will be 
asserted when either the Command Word or Configuration/ 
Status word I/O handshake protocol is violated (e.g., 
10 ms handshake response limit is exceeded). 

A command transfer attempt should not be initiated if 
the drive's COMMAND COMPLETE interface line is negated. 

i. Invalid or TJnimplemented Command Fault (Bit S) 

This bit is asserted when any of the following 
conditions are detected by the drive: 

1. A Command Function (bits 15. 14, 13, and 12 of the 
command word) defined as reserved in the ESDI 
specification is received. 

2. A Command Function plus Command Modifier defined as 
reserved in the ESDI specification is received. 

3. A legal ESDI command which is not implemented by 
the drive is received. 

4. A legal ESDI command with an invalid command 
parameter is received (e.g., illegal seek address, 
etc. ) . 

j. Seek Fault (Bit 4) 

This bit is asserted when the drive detects a problem 
with its actuator electronics or mechanism(s) . This bit 
is asserted when the Drive is unable to maintain the 
Read/Write heads within the recording zone of the media. 

If the Seek Fault bit is asserted the controller should 
attempt to Reset the Standard Status, send a RTZ 
command and reissue the SEEK command a minimum of three 
times prior to defining the drive as inoperable. 

NOTE 

It is the controller's responsibility to 
verify that a Seek Command resulted in an 
actuator movement to the desired physical 
track. 



-53- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 

11.2.3.2 (continued) 

k. Write Gate With Track Offset Fault (Bit 3) 

This bit is asserted when the drive actuator is 
offset from the normal On Cylinder location and the 
controller asserts the WRITE GATE signal. Writing to 
the drive media will be inhibited. If this bit (bit 
3) is asserted the controller should return the 
actuator to zero offset, reset Standard Status and 
then reattempt the write function. 

1. Vendor Unique Status Available (Bit 2) 

This bit is asserted to indicate that additional 
Vendor Unique Status is available in the Vendor 
Unique Status word(s). 

m. Write Fault (Bit 1) 

This bit is asserted to indicate that a Write Fault 
condition has occurred in the drive and that further 
writing will be inhibited until the fault is cleared. 

NOTE 

The interface Attention signal will be 
asserted in teal time when the Write Fault 
condition is detected. The controller 
should inhibit writing as soon as the 
Attention is detected to enable the 
controller to ascertain on which sector the 
write fault occurred. 

The following conditions will create a write fault: 

1. Write current in a head without Write Gate 
Asserted or no write current with Write Gate 
Asserted and Drive Selected. 

2. Write Gate asserted and multiple heads selected, 
no head selected or heads improperly selected. 

3. Write Gate and the head not M On Cylinder". 

4. Write Gate and Read Gate both asserted. 

5. Write Gate and power supply voltages not within 
tolerance. 



-54- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 

11.2.3.2 (continued) 

The controller should attempt to reset the Write 
Fault at least three times prior to defining a drive 
as inoperable. 

n. Removable Media Changed (Bit 0) 

This bit will always be zero for the WREN III drives. 

11.2.4 Transfer Ack 

Refer to ESDI Specification Section 5.2.4. 

11.2.5 Attention 

Refer to ESDI Specification Section 5.2.5. 

11.2.6 Index 

This signal occurs once per revolution or 16.68 ms nominal. 
The asserted pulse width is 16 times the reference clock 
period or 1.596 us, +1.0%. 

Refer to ESDI Specification Section 5.2.6 and Section 5.0 
of this document. 

11.2.7 Sector/Byte Clock/Address Mark Found 

The WREN III supports the controller soft sector (ADR Mark) 
and drive hard sector (Sector Pulses) format modes. Refer 
to Section 12.0 for configuration information, and to ESDI 
Specification Section 5.2.7 and Section 5.0 of this 
document. 

11.2.7.1 Sector (Drive Hard Sector) 

Refer to ESDI Specification section 5.2.7.1 

The Sector Pulse asserted pulse width is 16 times the 

reference clock period or 1.596 us +1.0%. 

11.2.7.2 Byte Clock 

Not supported by the WREN III. 

11.2.7.3 Address Mark Found (Controller Soft Sector) 
Refer to ESDI Specification section 5.2.7.3. 

11.2.8 Command Complete 

Refer to ESDI Specification Section 5.2.8. 

Command Complete will be asserted (following a negation) in 
the following cases: 

-55- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 
11.2.8 (continued) 

1. After a drive logic initiated recalibration function 
ftas been completed. 

2. After a received command has been executed with no 
detected error (and the actuator is on cylinder). 

3. After the requested information has been sent to the 
controller via the CONF1G-STATUS line. 

4. After a Command Transfer or Configuration Status 
Transfer or command execution has been terminated due 
to a detected fault condition. 

11.3 DATA TRANSFER LINES 

Refer to ESDI Specification Section 5.3 

The nominal data transfer rate is 10.0 MHz which will result 
in a Read/Write Clock period (T) of 100 ns in Figure 21 of 
the ESDI Specification. 

11.4 READ. WRITE. AND FORMAT PARAMETERS 

Refer to ESDI Specification Section 5.4 except 5.4.3.5 and 
5.4.4.5 which are not applicable. The intersector gap is 16 
bytes long and is oriented to begin four bytes before a 
sector (Index) pulse. 

Read propagation delay ranges between 7 and 9 bit times. 

Write propagation delay ranges between 4 and 6 bit times. 

The PLO Sync Field length is 11 bytes minimum. See also 
Configuration Data Specifications in Section 11.2.3.1 of 
this specification. 

NOTE 

Format Speed Tolerance gaps are not required for the WREN 
for a Fixed Sector Format (Figure 22 of the ESDI 
Specification) . 

ESDI fixed sector drives (e.g. WREN III) require that a PLO 
sync pattern be written prior to each read function boundary 
(see 5.1.7 in the ESDI Specification). The WREN III will 
automatically write the required sync pattern but the 
controller must define the point at which the PLO sync 
pattern is to be written. A header PLO sync field write is 
initiated by the trailing edge of ADDRESS MARK ENABLE with 
WRITE GATE asserted. A header or data PLO sync field write ' 
is initiated with the leading edge of WRITE GATE whilt 
ADDRESS MARK ENABLE is negated. The format function 
initiated by the host must define the point at which the PLO 
sync pattern is to be written for each address and data 
field written. 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-B 



11.5 DEFECTS LIST 

The WREN III provides media defect information in 
accordance with, the ESDI Specification. Refer to ESDI 
Specification Section 5.5 for details. 

The CRC seed will be zero. The byte sync characters are 
included in the CRC written. 

12.0 OPTIONS 

All options are either incorporated or packaged at the 
manufacturing facility. 

12.1 DRIVE CONFIGURATION SWITCHES 

The WREN III is configured by turning on/off the switches 
in SW1 on the Servo PWB. SW1 is located behind the front 
panel as shown in Figure 13. These switches will be set at 
the factory to be shipped with SWl-l OFF, SW1-2 ON. SW1-3 
ON and SW1-4 OFF. 



12 3 4 




FIGURE 13. CONFIGURATION SWITCH LOCATIONS (See Table 6.) 

-57- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 77738212-D 

12.1 (continued) 

Table 7 shows the options that can be selected using SW1. 
(Reference Figure 13.) 

TABLE 7. WREN III OPTION SWITCH SETTINGS 



SWITCH PURPOSE 



MOTOR OPTION 



SW1-1 



OPTION 



SECTOR MODE 
SELECT AND 
DEFAULT SECTOR 
SIZE 



OFF 






ON 






SW1-2 


SW1-3 


SW1-4 


OFF 


OFF 


OFF 


ON 


OFF 


OFF 


OFF 


ON 


OFF 


ON 


ON 


OFF 



MOTOR START ON POWER UP [1] 
MOTOR START WITH COMMAND [2 J 



64 SECTORS PER TRACK 

35 SECTORS PER TRACK 

3 6 SECTORS PER TRACK 

34 SECTORS PER TRACK 



CU 



OR 



ADDRESS MARK 
MODE SELECT 



ON 



ON 



ON 



SOFT SECTOR OPERATION [3] 



[1] Drives are shipped with these switch settings. 

[2] When the SW1-1 switch is on. a MOTOR ON command is required 
from the controller to start the spindle motor. When power 
is applied to the drive, the drive will generate an 
ATTENTION signal and assert Standard Status Bits (Section 
11.2.3.2) 8 and 9 signifying "Power On Reset Conditions 
Exist" and "Spindle Motor Stopped". The controllec must 
then respond with a command to Reset the Interface 
ATTENTION line and also the Start Motor Command in or dec to 
start the spindle motor. 

NOTE 

This procedure is required anytime that the 
"Power On Reset Condition Exists" status bit 
is received by the controller if the "Motor 
Control Implemented" switch is on. 

[3] See paragraph 12.4. 



-53- 



PRODUCT SPECIFICATION FOR WREN III DISK DRIVE MODEL 94166 7773 8212-B 



12.2 FRONT PANEL 

The WREN III is available with a black front panel. The 
panel has a single ced rectangular LED which indicates the 
drive is selected when glowing. A flashing LED indicates 
the presence of a nonrecoverable fault. A fault indication 
is displayed irrespective of DRIVE SELECT status. 

12.3 CUSTOM FORMATTING 

The WREN III is formatted during production. CDC maintains 
custom formatting capability which can incorporate many of 
the unique formats used in the Winchester marketplace. A 
majority of special format requirements can be implemented 
as specified. 

12.4 SOFT SECTOR OPTION 

The WREN III supports the use of the soft sector format as 
described in the CDC ESDI Specification. 77738076. Section 
6.4.4. 

To implement the optional soft sectored format operation, 
select "Address Mark" mode in the WREN III by positioning 
option switches SW1-2, SW1-3 and SWl-4 to the ON position. 
See Figure 13 and the table following it. 

12.5 SINGLE UNIT SHIPPING PACK 

The WREN III is normally shipped in bulk packaging to 
provide maximum protection against transit damage. Units 
shipped individually require additional protection as 
provided by the single unit shipping pack. Users planning 
single unit distribution should specify this option. 

13.0 ACCESSORIES 

All accessories are designed for implementation by the 
customer. 

13.1 FRONT PANEL KIT 

Same as 12.2 but includes all mounting hardware to support 
field installation. 

13.2 SINGLE UNIT SHIPPING PACK KIT 

Same as 12.5 except kit provides the necessary packing 
materials required to package and ship one WREN III device 
to be supplied by the user. 



-59- 



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