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OOOOThe  Boston  Computer  Society 

SINCLAIR-TIMEX  USER  GROUP  NEWSLETTER 


Volume  3  Issue  3 


POLYGONS 
by  John  Kemeny 

One  of  the  best  features  of  the 
T/S  2068  computer  is  its  ability 
to  create  and  display  high 
resolution  graphics.  There  are 
commands  in  T8  BASIC  to  PLOT 
points,  DRAW  lines,  and  even 
make  CIRCLES  and  arcs.  This 
article  will  present  subroutines 
to  draw  equalateral  trianges, 
squares,  penta-hexa-hepta-  octa- 
nona-deca-  and  other  polygons. 

Polygon  shapes  have  equal  sides 
and  equal  angles.  In  addition, 
we  hope  to  demonstate  in  this 
article  something  about 
developing  programs  and  making 
them  more  efficient. 

Let's  start  with  the  inputs  (see 
figure  1).  We  need  to  know  the 
coordinates  for  the  center,  0, 
and  the  radius,  0A. 

10  INPUT  "CENTER’S 
COORDINATES"’ X, Y 
20  INPUT  " RAD I US "’R 

The  x-coordinate  should  be 
between  0  and  255,  and  the  y 
between  0  and  175.  Also,  the 
radius  should  be  small  enough  so 
that  the  polygon  won't  go  off 
the  screen,  i.e.,  we  won't  do 
what's  known  as  "clipping."  To 
enforce  our  "shoulds"  we  can  add 
the  following  linet 

25  IF  X-RCO  OR  X+R>255  OR  Y-RCO 
OR  Y+R>175  THEN  SOTO  10 

We  also  need  to  know  the  number 
of  sides. 


POLYGONS  page  6 


March  1964 


FEBRUARY  MTG 
M I GHL X GHTS 

With  Sue  at  home  in  Waterbury 
recuperating  from  her  automobile 
accident,  the  February  meeting 
was  chaired  by  John  Kemeny.  He 
spoke  briefly  about  the  propsed 
new  library  policy,  asked  for 
volunteers,  told  us  about  a 
machine  code  newsletter  in 
Albany  NY,  and  plugged  the  March 
meeting  of  our  machine  language 
group. 

The  group’s  library  is  now  being 
kept  at  the  BC8  office  (1  Center 
Plaza,  Boston).  It  will  no 
longer  be  brought  to  meetings 
and,  if  we  can  get  a  volunteer 
to  be  the  1 ibrarlan,  things  can 
be  checked  out  from  there  one  or 
two  nights  a  month.  As  always 
the  group  needs  volunteers  for 
various  jobs.  John  is  organizing 
a  project  to  index  all  the 
exchange  newsletters  we’ve 
received,  and  we  need  volunteers 
to  help  put  out  our  own 
newsletter. 

The  Albany  machine  language 
group  associated  with  Bonnie  and 
Clyde  Software  is  publishing  a 

HIGHLIGHTS  page  4 


1  o  REM 


TAKE  THE  MONEY  AND  RUN 


Timex  was  involved  with  Sinclair 
computers  -from  the  very 
beginning.  Early  Sinclair 
machines  were  manu-f actered  to 
Sinclair  specs  at  a  Timex 
■factory  in  Scotland.  One  can 
speculate  that  this  close 
association  led  to  Timex ' s  later 
role  in  this  story. 

Now  Timex  has  dropped  out  of  the 
personal  computer  market  and  it 
makes  me  wonder  about  their 
motivations  from  the  very  start. 
There’s  no  evil  in  a  company 
finding  itself  in  financial 
difficulties  and  having  to  close 
a  part  of  their  business  to  save 
the  rest.  But  that’s  only  if 
the  company  was  parti ci pat i ng  in 
the  market  in  good  faith  in  the 
first  place.  Texas  Instruments 
had  to  abandi on  their  home 
computers  for  these  reasons  but, 
even  with  all  their  mis-steps,  I 
believe  they  real ly  wanted  to 
build  great  computers.  That, 
sadly,  is  not  always  the  case. 

Timex  brought  nothing  to  the 

microcomputing  community.  They 

never  made  any  serious  attempt 
to  promote  the  value  of  the 
Sinclair  products  nor  to  support 
the  community  of  users  that  grew 
around  the  machines.  When  there 
was  money  to  be  made  Timex 
accepted  it  and  when  things  got 
rough  they  pulled  out. 

I  am  a  capitalist  by  nature.  I 
have  absolutely  no  objection  to 
one  making  money,  lots  of  money. 


But  to  make  it  fairly  you  should 
produce  a  valuable  commodity. 
Make  some  good  contribution  to 
the  marketplace.  I  have  no 
inside  information,  but  I  feel 
that  Timex  never  had  any 
intention  of  adding  something  to 
the  home  computer  community. 

They  were  in  it  to  make  a  fast 
buck.  All  they  wanted  to  do  was 
take  our  money.  That's  not  good 
capitalism  and  I  think  it's  no 
coinci dence  that  Timex 
ultimately  f ai led.  And  perhaps 
no  surprise  that  the  whole  Timex 
Corp  is  in  trouble.  As  for  me 
I'm  now  giving  serious  thought 
to  ever  again  using  other  Timex 
products.  How  can  their  actions 
in  computers  not  reflect  on 
their  attitude  about  al 1  their 
other  customers  and  products. 

I’m  very  di ssappoi nted  with 
T  i-mex . 

A  Final  Notes 

The  grape  vine  says  that 
Sinclair  Research  is  on  the 

verge  of  signing  a  U.S. 
distribution  agreement  for  the 
Quantum  Leap  computer  with  The 
Betty  Crocker  Company. 

A  source  in  Sinclair  is  reported 
to  have  said  that,  "this 
agreement  will  pave  the  way  for 
the  QL  to  be  sold  in  thousands 
of  grocery  stores  and 
supermarkets  around  the 
country. " 


OThe 
O  Boston 
Q  Computer 

CT 


This  newsletter  is  produced  to 
inform  group  members  of  the 
agenda  and  logistics  of  future 
meetings,  as  well  as  to  recap 
and  amplify  the  information 
provided  at  the  meetings.  It 
also  provides  a  forum  for 
members  and  interested  parties 
to  communicate  what  thay  have 
learned  or  developed  relating  to 
Sinclair  and  Timex  computing. 
Meetings  are  open  to  the  public 
(non-member  admission  is  *3) ; 
however  attendees  are  encouraged 
to  join  the  Boston  Computer 
Society  (BCS)  This  newsletter 
is  free  to  members.  Back  issues 
are  one  dollar  each. 

DIRECTIONS  TO  MEETING:  The  S-T 
User  Group  meets  in  the  Large 
Science  Auditiorium  (Room  8/2/ 
009)  of  the  Uni versi ty  of 
Massachusetts,  Boston  Harbor 
Campus.  It  is  located  only  3 
miles  from  downtown  Boston  and 
easily  accessible  by  public  and 
private  transportation.  From 
the  north  or  west,  take  the 
Southeast  Expressway  to  Exit  17. 

Turn  left  onto  Columbia  Road. 
Follow  construction  signs  to  get 
to  Morrissey  Boulevard  in  the 
direction  of  UMASS  and  the 
Kennedy  Library.  Bear  right  on 
traffic  island,  get  in  the  right 
two  lanes,  following  UMass/ 
Boston  signs.  Turn  left  at  the 
light  into  Campus.  From  the 
south,  take  Morrissey  Boulevard 
northward  to  the  campus.  On  the 
MBTA,  take  the  Red  Line  (Ashmont 
Train)  to  Columbia  Station. 
Transfer  to  the  free  University 
shuttlebus  in  the  T  parking  lot. 


The  Sinclair  Timex  User  Group 

Sue  Mahoney 
Di rector 
c/o  BCS  Office 
or  203-755-2699 

Jack  Hodgson 
Publ i sher /Edi tor 
P.0.  Box  526 
Cambridge,  MA  02238 

617-354-7899 

John  Kemeny 

User  Group  Correspondent 
284  Great  Road,  Apt.  D5 
Acton,  MA  01720 


Allan  Cohen 
Meeting  Coordinator 
617-961-3453 


The  Si ncl ai r  Timex  Newsletter  is 
publ i shed  monthly  by  the 
Sinclair  Timex  User  Group  of  the 
Boston  Computer  Society. 
Membership  in  the  BCS  is  «24  per 
year  which  i ncl udes  a 
subscription  to  its  magazine 
"The  Computer  Update"  and 
subscription  to  two  of  its  group 
newsletters  (such  as  this  one)  . 

Advertising  space  is  available 
in  this  publ i cati on  on  a 
limited,  first  come  first  served 
basis.  The  rate  is  *60  per 
quart  page.  At  this  time  no 

other  *  sizes  are  available. 

For  detailed  rate  and  discount 
information  contact  the 
Advertising  Manager  or  the 
Pub  1 i sher . 


HIGHLIGHTS  continued 

newsletter.  Free  sample  copies 
are  avai  lable  if  you  send  them  a 
card  requesting  it.  Ron  Barnard, 
Bonnie  and  Clyde  Software,  36 
Tanglewood  Rd. ,  Albany  NY  12205. 


Henry  April  of  EZ  Key 
demonstrated  Upload  2000.  This 
is  a  program  for  the  TS2068 
which  helps  you  to  convert 
TS 1 000  family  programs  to  run  on 
the  2068.  The  main  limitation 
is  that  the  source  program  must 
be  100%  in  BASIC.  Also  some  of 
the  TS1000  commands  have  to  be 
translated  by  hand  after  the 
UPLOAD  program  has  done  most  of 
the  transl ation.  Henry  also  told 
us  that  he  will  be  distributing 
the  Compusa  Disk  Drive  system 
for  the  TS 1000/ 1500  computers. 

EZ  Key,  Sui te  75,  711  Southern 
Artery,  Quincy,  MA  02169. 

Jack  Hodgson  took  a  couple  of 
quick  show-of  —hands  surveys  of 
the  audience.  Of  the  29  people 
theres  9  owned  TS2068's,  3  owned 
TS1500’ s,  and  near  100%  owned 
TS1000/ZX81 ’ s.  Roughly  80%  had 
been  to  6  or  more  meetings,  20% 
had  been  to  less  than  6  and 
about  6—8  people  were  there  for 
the  first  time. 


THE  DEMISE  OR- 

T I MEX  COMPUTER 
CDRPORAT  I  OIM 

(or  What  Is  To  Become  Of  The 
Timex  Sinclair  Owners) 

By  Susan  C.T.  Mahoney,  Director, 
Sinclair  Timex  User  Group 

I  was  one  of  the  first  people  to 
learn  that  Timex  was  getting  out 
of  the  personal  computer  retail 
market.  A  friend  of  mine,  who 
was  working  there  called  me  to 
tell  me  the  news,  just  minutes 
after  she  received  the  word 
hersel f . 


My  first  reaction  was  that  it 
was  hard  to  believe,  although 
Timex  had  suffered  some 
setbacks,  it  was  looking  like 
they  might  make  it.  Especially 
with  all  the  good  reviews  of  the 
TS  2068  and  the  new  peripherals 
that  were  about  to  be  marketed, 
e.g.,  the  modem,  the  80  column 
printer,  the  microdrive. 

I  remember  initially  feeling 
like  a  member  of  my  immediate 
f ami ly  had  died.  I  personal ly 
have  been  involved  with  both 
Sinclair  Research,  Ltd.  and 
T i mex  Computer  Corporation  si  nee 
August  of  1981 .  I  had  observed 
first  hand  the  exci tment  and 
enthusiasm  that  the  Sinclair  and 
Timex  computer  products  had 
generated  from  its  owners  and 
users,  not  to  mention  all  of  the 
more  than  500  third  parties  that 
had  developed  products  to 
support  the  TS  computers. 

In  addition  I  had  worked  for 
Timex  and  experienced  being  laid 
off  myself,  I  knew  exactly  what 
those  24  people  were  feeling, 
after  being  told  to  get  their 
personal  belongings,  since  they 
no  longer  worked  there.  Some 
people,  like  my  f ormer  boss  had 
worked  for  Timex  for  23  years, 
it  is  not  easy  to  pick  up  the 
pieces  and  go  on.  To  these 
people  I  wish  them  the  best. 

After  a  good  night’s  sleep,  I 
began  to  realize  that  this  did 
not  represent  the  end,  in  fact 
after  reading  several  accounts 
of  thi s  d i smant 1 i ng  in  var i ous 
newspapers  and  talking  with  a 
variety  of  individuals, 
including  Timex  and  Sinclair 
spokespersons  I  was  feeling  much 
more  hopeful .  Some  of  the 
reasons  for  this  included! 

1.  Sinclair  is  still  in 
business.  We  have  an  unusual 
situation  in  that  Timex  was  the 
distributor  for  the  computer 


only  in  North  America  and  a  few 
European  countries.  Sinclair 
Research  is  still  marketing  the 
ZX81  and  the  ZX  Spectrum  in  the 
United  Kingdom  and  the  rest  of 
the  world. 

2.  Sinclair’s  newest  computer, 
the  QL  or  the  Quantum  Leap  has 
been  very  well  received  in  the 
UK.  Sinclair  Research  will  be 
marketing  it  here  in  the  US  this 
fall  along  with  their  flat 
screen  tv. 

3.  Mike  Jacobi ,  the  Marketing 
Director  for  Timex,  stated  that 

the  marketing  and/or 

manufacturing  rights  for  the  TS 
2068  are  up  for  negotiation, 
which  means  that  ei ther  Si ncl ai r 
could  get  the  rights  back  for 
the  TS  2068  or  some  third  party 
could  get  the  rights  to  the 
computer. 

Presently,  Sinclair  Research 
denies  any  i ntenti on  to  market 
any  computer  but  the  QL,  but  I 
have  seen  this  type  of  si tuat i on 
change  before.  Al so,  the 
opportunity  for  a  third  party  to 
step  in  could  mean  that  an 
existing  company  could  come  in 
and  take  over  the  marketing 
rights  or  a  new  company  could  be 
formed  of  individuals  who  had 
the  right  combination  of  capital 
and  understanding  of  the  TS 
community. 

This  could  work  to  the  benef i t 
of  the  present  owners  and  third 
party  manuf acturers/marketers. 
With  the  right  company  in 
charge,  we  could  see  even  more 
cooperation  in  dissemination  of 
information  between  these 
groups. 

Only  time  will  tell,  in  the 
meantime,  we  cannot  think  that 
this  whole  issue  is  over,  this 
is  not  like  Texas  Instruments 
announcing  that  they  are  getting 
out  of  the  personal  computer 


market.  There  are  a  few  more 
variables  at  play  here. 

What  are  we  to  do  in  the 
meantime?  For  one  thing,  I 
think  that  we  have  to  unite. 
Particularly  user  groups,  we 
need  to  form  a  tighter  network 
of  communication  between  our 
members  as  wel 1  as  between  user 
groups  across  the  country. 

One  concrete  suggestion  that  I 
can  give  is  for  user  group 
directors  to  poll  their  members 
ei ther  formally  or  informal ly  to 
determine  which  users  are  still 
interested  in  contining  with 
their  Timex  Sinclair  computers. 
Then,  if  we  could  gather  this 
data  to  disseminate  it  to  the 
third  parties  and/or  the  any 
perspective  investors  for  the 
Timex  marketing  rights,  we  would 
be  able  to  document  that  there 
is  a  viable  market  out  there ! 

That  it  is  worth  someone 
investing  more  money  for  product 
development  and  support  for  TS 
rel ated  software  and  hardware. 

As  for  Timex '  plans  for  the 
future,  they  will  continue  to 
honor  the  warranties  on  their 
existing  equipment,  and  they 
will  be  selling  off  thei r 
present  inventory  which  includes 
TS  1300,  TS  2068,  limited 
supplies  of  their  new  modem,  and 
existing  software.  The  fate  of 
their  80  column  printer  and 
their  microdri ve  are  right  now 
on  hold,  with  no  plans  to  market 
ei ther  of  the  1 atter  two 
products.  Basically,  anything 
that  was  produced  prior  to  the 
announcement  will  be  made 
avai 1 abl e,  but  no  new  product 
development  in  the  computer  area 
is  in  the  wind  for  now.  < I 
qualify  my  statement  because  I 
have  seen  things  change  too  many 
times  to  consider  anything 


MAHONEY  next  page 


MAHONEY  continued 

associated  with  either  Sinclair 
or  Timex  as  final.) 

I  recieved  many  calls  from  TS 
owners,  third  parties,  and  the 
press,  from  all  over  the  country 
and  the  UK,  expressing  concern 
about  what  the  future  will  be 
for  the  owners  of  the  Timex  or 
Sinclair  computers.  My  answer 
has  been  that  we  need  to  hang  in 
there,  not  to  give  up,  and  to 
remember  that  the  dust  has  not 
settled.  Me  have  an  opportunity 
to  influence  the  future  of  the 
Timex  Sinclair  line,  by  showing 
that  there  is  a  strong 
enthusiastic  market  sti 1 1  out 
there ! 

Our  group  will  be  glad  to  act  as 
a  clearing  house  for 
dissemination  of  information 
relating  to  the  Timex  or 
Sinclair  computers.  You  may 
contact  Jack  Hodgson  <617-354- 
7899)  or  myself  (203-755-2699) 
regarding  questions,  rumors, 
ideas  and  of  course  support. 

This  is  a  time  when  we  all  must 
pull  together  and  demonstrate 
our  i nterest . 


POLYGONS  continued 

30  INPUT  "NUMBER  OF  SIDES" 'N 


6 


From  now  on  we'll  consider  all 
angles  in  radians.  We  can 
develop  our  algorithm  using  a 
little  trigonometry . 

(If  you  want  to  create  computer 
graphics,  you  shouldn't  have 
slept  through  those  trig  cl  asset 
in  high  school . ) 

We’ll  draw  N  sides,  soi 

100  FOR  1-1  TO  N 

From  figure  2  we  can  see  how  to 
PLOT  ths  initial  point,  A. 

110  PLOT  X+RtCQS  P, Y+RtSIN  P 


Fi nal 1 y,  if  we  want  to  be  able 
to  draw  pol ygons  in  any 
orientation,  e. g. ,  a  4-gon  m 
ei ther  a  square  or  a  diamond,  we 
need  an  initial  orientation! 

40  INPUT  " OR I ENT AT  I  ON " ' P 

For  angles,  computers  general 1 y 
use  radians  instead  of  degress, 
that’s  what  the  Si ncl ai r-1 • max ’ 
expects  for  their  trig 
f uncti ons.  There  are  24PI 
radians  in  360  degrees.  If  »?e 
want  to  enter  the  orientation  ir 
degrees,  it  is  a  simple  matter 

tc  convert  it. 


e> 


F*  g  o  r  e 2- 


45  LL1  F=P#PI/180 


To  get  -from  A  to  B  we  have  to 
draw  the  vector  B-A.  Since  we 
have  N  ^slices  in  our  polygon 
"pizza"  and  2*PI  radian*  per 
"pie"  (2  pi’s  in  1?),  each 
slice,  like  angle  BOA,  has  2*PI/ 
N  radians.  Thus  drawing  vector 
B-A  is: 

120  LET  Q-P+24PI/N 

130  DRAW  R* (COS  Q-COS  P) ,  R*(SIN 

Q-SIN  P) 

To  continue  drawing  the  polygon 
we  need  to  repeat  (iterate)  this 
step  using  the  point  B  as  our 
starting  point.  We  can 
accomplish  this  by  changing  the 
"old"  initial  angle  P. 

140  LET  P-Q 
150  NEXT  I 

This  is  our  first  algorithm. 

Stop  and  try  it.  Enter  80  and 
80  for  the  center,  60  for  the 
radius,  8  for  the  number  of 

sides,  and  PI/8  radians  (or  22.5 
degrees)  for  the  orientation. 

This  algorithm  is 
strai ghtf orward,  but  not  very 
efficient.  To  make  it  run 
faster  we  can  try  to  shorten  th« 
work  done  inside  the  1 oop .  This 
may  lead  to  a  1 onger 
initialization,  but  it  saves 
execution  time  because  the  work 
done  inside  the  loop  isn’t 


repeated.  For  example,  let’s 
add  line  50  and  change  120t 

50  LET  V-2IPI/N 
120  LET  Q»P+V 

This  saves  some  calculation 
time.  But  our  real  probl em  is 
that  each  iteration  of  the  loop 
requires  six  trig  functions  (SIN 
and  COS)  to  be  evaluated.  Can 
improve  on  this?  Look  at  figure 
3.  Note  that  the  1 ength  of  each 
vector  is  the  same.  Call  this 
length  8.  Also  note  that  the 
angle  of  the  vectors,  cal 1  it  T, 
keeps  changing  by  2*PI/N  radians 
in  each  iteration  (going 
counterclockwise) .  Let’s  modify 
our  algorithm  by  changing  line 
130  and  adding  135i 

130  DRAW  StCQS  T,  StSIN  T 
135  LET  T-T+V 

We  must  remember  to  initialize  8 
and  T  (derivations  are  left  as 
exercises  for  the  reader) . 

60  LET  S«2*R*SIN(V/2> 

70  LET  T-P+PI/2+V/2 

In  addition,  since  Q  is  no 
longer  used  in  line  130,  we  can 
consol idate  by  deleting  line  140 
and  changing  line  120  toi 

POLYGONS  next  page 


POLYGONS  continued 

120  LET  P-P+V 

There  is  a  second,  faster, 
algorithm.  Let's  look  next  at 
moving  the  PLOT  statement 
outside  the  loop.  In  theory,  a 
new  side  starts  where  the 
previous  one  left  off.  But  the 
fact  that  we  are  working  on  a 
high,  yet  finite,  resolution 
computer,  and  not  an  ideal 
mathematical  plane,  can  get  us 
in  trouble.  Because  in  practice 
a  roundoff  may  cause  our  point 
to  be  one  tiny  pixel  off . 

Unf ortunatel y,  this  condi t i on  is 
cummul ati ve  over  the  sides,  so 
the  net  result  can  be  a  polygon 
that  doesn't  close  properly. 

But  do  not  abandon  hope !  For 
small  values  of  N  the  effect  is 
negligible;  and  pol ygons  with 
many  sides  aren’t  really 
distinguishable  from  circles 
anyway.  So,  to  create  this 
third  algorithm,  move  line  1 10 
to  80  and  delete  line  120. 

Notice  how  little  is  left  in  the 
loop.  Further  speedup  is 
possible.  For  example,  we  could 
replace  the  FOR/NEXT  control 
structure  with  an  IF  THEN  and 
GOTO.  Another  idea  is  to  use 
table  lookup  methods  to  compute 
the  trig  functions.  Finally,  we 
could  always  resort  to  machine 
cod#.  Having  identified  and 
boiled  down  the  bottleneck,  i 
the  loop,  greatly  simplifies 
using  machine  code  for  the 
problem. 

Let's  finish  with  a  flourish. 

Add  a  new  input  and  change  line 
50  to: 

49  INPUT  "HOPS" 'H 

50  LET  V=2*PI*H/N 

Try  center  80  and  80,  radius  60, 
sides  5,  orientation  18  degrees, 
and  2  hops.  Why  do  you  think  we 
called  it  "hops"? 


FINAL  POLYGON  ALGORITHM 

10  INPUT  "CENTER’S 
COORDINATES" ’ X,Y 
20  INPUT  "RADIUS" ’ R 
25  IF  X-R<0  OR  X+R>255  OR  Y-R<0 
OR  Y+R>175  THEN  GOTO  10 
30  INPUT  "NUMBER  OF  SIDES" ' N 
40  INPUT  "ORIENTATION" 'P 
45  LET  P*P*PI/180 

49  I NPUT  " HOPS " ' H 

50  LET  V»2*PI*H/N 

60  LET  S-2*R*SIN(V/2> 

70  LET  T*P+Pl/2+V/2 

80  PLOT  X+RSCQS  P,  Y+R*SIN  P 

100  FOR  I»1  TO  N 

130  DRAW  StCOS  T,  S*SIN  T 

135  LET  T»T+V 

150  NEXT  I 


LANGUAGE 
GROLJF*  HIGHLIGHTS 

Mitch  Russo  of  Zilog,  who  was 
scheduled  to  speak  to  us  in 
March  was  taken  ill  and  his 
appearance  will  be  rescheduled 

for  a  later  month.  In  his  place 
«a  held  a  free  form  discussion 
on  a  number  of  M/L  topics. 
Answering  each  other’s  questions 
and  passing  on  bits  of 
information. 

The  bulk  of  the  evening  was 
occupied  by  Dave  Miller  telling 
us  about  his  experiences  working 
with  EPROM’ s  (erasable 
programmable  read  only 
memories).  Dave  is  designing 
applications  that  will  load 
instantly  by  using  cartridges 
instead  of  cassettes. 

Also  he’s  taken  the  entire 
TS1500  ROM,  corrected  the  bugs, 
added  a  couple  of  custom 
features  and  put  it  into  his 
TS1000  computer.  He  is  working 
with  an  EPROM  burner  which  he 
built  from  plans  in  the  ill- 
fated  SO  magazine.  He  says  he 
uses  mostly  Intel  2716  and  TI 
2516,  2K  X  8,  EPROMS.  For  more 


MUUUWUUUUU 


Uiitmu 


info  about  Dave’s  work  you  ca 
contact  him  through  this 
newsletter  or  at  our  next  M/L 
meeting. 


Speaking  of  the  next  meeting. 
Because  Bob  Heath  has  moved  to  a 
new  assignment  it  will  no  longer 
be  possible  for  us  to  meet  at 
ITEK.  He  is  currently  looking 
for  a  new  location  (any 
suggestions?).  In  the  meantime 
the  April  meeting  has  been 
cancelled.  Check  this  column 
next  month  for  the  new  location 
or  call  Jack  Hodgson  (617-354- 
7899) 


ARROW 


This  adaptation  of  a  perennial  gaire 
format  features  the  fastest  movemant 
programmable  in  BASIC  on  the  Sinclair. 
Characters  are  POKEd  directly  into  the 
portion  of  the  memory  beginning  at  16396 
known  as  the  Display  File.  Scoring  occurs 
when  positions  in  the  same  file  are  PEEKed 
to  see  if  they  are  already  occupied. 

The  listing  is  annotated  using  variable 
names  which  can  be  abbreviated  to  one 
letter  for  typing  in.  Timing  Loops  are 
used  instead  of  the  PAUSE  ccnmand.  The 
PRINT  staements  after  line  900  indicate 
bytes  used  by  this  program.  As  given  WORM 
will  run  in  2K  or  16K  on  a  T/S  1000. 

For  IK  ZX81's,  emit  instructions  and 
scoring  messages  as  well  as  auto-run. 

You  may  want  to  remove  one  re jw  from  the 
playing  field  as  well. 

The  INKEY$  routine  in  line  110  is 
perhaps  the  shortest  way  to  implement 
all  four  directions  in  one  statement. 

Other  characters  may  be  POKEd  into  the 
field,  but  some  of  these  will  trigger 
lockup  or  a  crash. Line  110  can  also  be 
adapted  to  work  with  a  joystick  such 
as  described  elsewhere  in  this  issue. 

This  approach  to  manipulating  the 
Display  File  is  worth  investigating  as 
the  first  step  towards  understanding  the 
machine  code  possibilities  of  our 
machines . 


HARDER 


N  GO 
THEN 


2  =  HARDER 
CORE  +  10 
,5; SCORE 


GRAPH  1 6K 
by  Hark  Tepper 

Here  is  a  program  to  draw  a  bar 
graph.  When  it  runs  you  must 
enter  20  numbers,  greater  than  0 
but  less  than  40.  My  goal  in 
writing  the  program  was  to  keep 
it  as  short  as  possible,  thus  it 
doesn't  offer  fancy  borders, 
variable  range  for  numbers,  etc. 
The  program  illustrates  a 
plotting  technique  you  can  use 
in  other  programs. 

10  REM  ***  TS1000  GRAPH  PROGRAM 

20  LET  Y  *  4 

30  DIM  A (40) 

40  FOR  T  =  1  TQ  20 
50  INPUT  A (T) 

60  NEXT  T 
70  LET  T  «  1 

80  FOR  Z  *  1  TO  20 

90  FOR  R  *  1  TO  A (T) 

100  PLOT  Y, R 
110  NEXT  R 
120  LET  T  T+l 
130  LET  Y  =  Y+2 
140  NEXT  Z 

150  PRINT  AT  16,0?  "10" 

160  PRINT  AT  11,0?  "20" 

170  PRINT  AT  6,0;  "30" 

180  PRINT  AT  1,0?  "40" 


In  the  "lift's  stmrt  a  rumor" 
depts 

MAG  I  G  NEXUS  ST  X  FRO 
LANGUISH 

(The  above  title  i ■  a  wonderful 
anagram  for  SINCLAIR-TIMEX  HUGS 
SAMSUNG  AID. ) 

Let  me  elaborate  on  this 
potentially  good  news.  The 
March  12th  edition  of  Electronic 

News  reported  that  Sinclair 

Research  Ltd.  ham  signed  a 
licensing  agreement  with  Samsung 
Electronics  of  South  Korea 
wherein  Samsung  will  assemble 
and  market  the  ZX81  and  Spectrum 


computers  in  South  Korea. 

Samsung  will  use  Sinclair  parts 
and  expects  products  by  the 
fourth  quarter. 

What  does  this  mean  to  the  Timex 
-less  U.8.  market?  There  are 
three  more  ingredients  needed  to 
make  this  into  a  truly  great 
rumor.  First,  the  South  Korean 
electronics  industry  is  geared 
for  export |  the  average  Korean 
can’t  afford  color  TVs  and  VCRs. 

Second,  Samsung  is  a  huge 
company  and  a  big  exporter  to 
U.S.  department  stores.  For 
example,  many  of  the  "no  name" 
brand  TVs  in  these  stores  are 
produced  by  Samsung.  Finally, 
al though  perhaps  an  unrelated 
fact,  the  T/S  2068s  were  being 
assembled  in  South  Korea. 
Conclusions — I'll  leave  you  to 
draw  your  own. 


ZEBRA  JOYSTICK 

by  Will  Stackmaun 


The  joystick  adaptor  available  from 
Zebra  Systems  of  Woodhaven,  N.Y.  is  an 
easy-to-use  hardware  add-on  driven  by  a 
9  byte  MC  routine,  compatible  with  Atari 
type  "sticks".  With  its  routine  in  1  REM, 
the  user  can  adapt  any  program  where 
INKEY$  would  be  used  used  to_ accept  an 
input.  Thus  this  interface  could  also 
be  used  to  accept  up  to  9  external  switches 
for  sane  practical  applications  as  well 
as  gaming.  The  device  is  well-made  but 
barely  shielded.  It  is  possible  to  loosen 
the  connector  socket  connections  which 
are  push-fit.  There  is  no  trouble  plugging 
additional  peripherals  onto  the  expansion 
connector  provided.  The  USR  routine  can 
of  course  be  located  above  RAMT0P  allowing 
a  number  of  programs  to  be  loaded  under 
it. 


ZXLR8 
by  Will  Stackman 


The  leisurely  LQADing  speed  of  Sin¬ 
clair  computers  has  been  a  drawback 
since  their  inception .  Several  systems 
are  available  to  overcome  this  handicap. 

The  ZXL8R  program  package  from  G. Russell  is 
the  most  economical  and  quite  satisfactory. 
Rather  than  depend  on  a  hardware  filter 
or  an  elaborate  checksum  procedure,  this 
method  of  increasing  LQADing  speed  first 
has  the  user  calibrate  the  program  to  a 
particular  cassette  recorder.  The  data 
received  from  the  calibration  program  is 
then  used  to  adjust  the  main  program  when 
LQADing  or  SAVEing. 

The  ZXL8R  is  actually  a  miniature  oper¬ 
ating  system,  allowing  data  as  well  as 
program  IGADs.  Since  all  programs  must  be 
IDADed  by  title,  there  is  also  a  utility 
for  scanning  a  tape  to  list  all  titles. 

Use  of  this  system  takes  seme  practice,  but 
the  documentation  is  adequate.  If  programs 
are  SAVEd  at  lower  calibration  speeds  (for 
more  reliability)  there  is  a  good  chance 
they  can  be  reDQADed  on  similar  machines. 
Since,  as  the  name  implies,  this  program 
speeds  op  the  signal  to  the  x'ecorder,  which 
raises  its  pitch,  the  machine  used  must 
have  good  treble  tone  and  properly  aligned 
heads.  Strangely  enough,  the  Winky  Board 
doesn't  seem  to  help  when  used  with  this 
system. 


SO  Ml  EE  NAMES 
AT  TIMEX 

Here  are  a  couple  of  useful 
names  of  people  who  still  work 
at  TIMEX  Computers. 

Elaine  Cristillo,  203-573-6815. 
Elaine  is  involved  with  third 
party  documentation. 

Cathy  Hoolihan,  203-573-5246. 
Cathy  is  the  person  to  talk  with 
if  you  want  to  buy  products 
direct  from  TIMEX. 


USR  832 
by  Mike  Coughlin 

So  you’ve  loaded  the  copy 
protected  program  you  spent  the 
last  month  writing  on  your 
TS1000/ZX81,  and  it’s  so  well 
protected  that  the  keyboard 
doesn’t  work.  Not  only  that  but 
you’ve  only  got  one  copy.  Serves 
you  right!  But  there’s  a  little 
known  trick  (first  described  in 
Syntax )  that  will  come  to  the 
rescue. 

Instead  of  using  the  normal  LOAD 
"name"  comand,  use  a  USR  call. 

The  LOAD  and  SAVE  routines  are 
unusual  since  they  require  a 
name  string  as  input.  The  syntax 
checker  doesn’t  like  strings 
after  a  USR  call.  But  there  are 
two  statements  that  wi 1 1  work. 

LOAD  CHR*  USR  S32  “name",  or 
SAVE  CHR*  USR  632  "name" 

The  USR  832  statement  will  start 
the  LOAD  routine,  the  CHR* 

converts  whatever  is  left  from 
USR  to  an  acceptable  input  to 
LOAD  and  SAVE  and  the  whole 
combination  gate  past  the  syntax 
checker.  SAVE  CHR*  832  ""  is  the 
more  usual  form.  First  your 
intractable  program  will  be 
loaded  and  before  it  can  do  any 
f uny  business  the  save  routine 
will  execute.  If  you’ real  quick 
(you  have  five  seconds)  you  can 
switch  tapes  and  make  a  copy. 

As  soon  as  you  see  the  blank 
screen  and  the  pattern  from  the 
SAVE  routine,  you  can  hit  space 
and  the  program  will  be  loaded 
but  "unlocked"  from  any  machine 
code  or  BASIC  statements  that 
normal  1 y  run  i mmedi atel y .  You 
can  LIST  and  change  BASIC 
statements,  or  ref er  to  your 
detailed  notes  and  POKE 
corrections  to  your  machine 
code.  You  did  keep  detai 1 ed 
notes  didn’t  you? 


i 


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a  16K+  file  manager  for  the  Timex 

ZX  PRO/FILE  is  a  machine  language  data  base 
that  gives  you  tremendous  versatility: 

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♦files  of  any  size  in  the  same  program  run 
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A  59  page  manual  comes  with  the  cassette.  In  it 
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ZX  PRO/FILE  is  the  best  file  manager  you  can 
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Let  me  send  you  full  specifications.  Write  to: 

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Phone:  (603)  586-7734 


OOThe  Boston 
OG  Computer  Society 

Three  Center  Plaza 
Boston,  MA  02108 
617-367-8080 


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Permit  1138 
Boston,  MA 


Circle  Chess  Group 
A.  F.  Stanonis 
P.O.  Box  63 

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