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TIMER SINCLAIR USERS CLUB | NEWSLETTER

Toronto, Опіагіо |

EXECUTIVE OFFICERS

PRESIDENT: George Chambers (416) 751-7559 LIBRARIAN: Martin Mauk - tapes John Burns - magazines ASS'T LIBRARIANS: D. Cooper ` T. Haller TREASURER: Greg Lloyd NEWS EDITORS: John Roach (416) 447-7784

ACTIVITY DIRECTOR: Cameron Hayne LIAISON OFFICER (Out-of-town members): George Chambers Mike Mitchell

LETTER FROM THE PRESIDENT

Over the past couple of months we have had quite a few new members join our club, I am sure they hope to benefit from association with other T/S users, and often their hopes are realized. However, in the rush of things, I am sure some of them tend to get lost in the shuffle, and ultimately lost to the club.

I would like to take this opportunity to welcome each and every one of you to our club, Use it, ask questions at meetings, borrow from our library, read the newsletter. Not the least important, contribute to the club activities. From my experience, you will profit immensely from the give and take of a more active role in the club. The invitation is extended; seize it. Cameron Hayne has done this, and has agreed to be our new Activities Director. He will be responsible for providing the demo's, talks, etc. at each meeting. Welcome to the executive, Cameron. We're pleased to have you.

Yours in computing George Chambers (President)

NOTES FROM THE EDITOR

If you have an article you would like published in the newsletter, give it to any member of the executive during the meeting or mail

it to SINC-LINK c/o J. Roach, 56 Pachino Blvd., Scarborough, Ontario MIR 4J7.

Dan Sauve reports that nobody showed up at the 2 get-togethers he called to form a hardware SIG. He's still enthused - call him at 251-5623 if you're interested.

SYNCBITS Ian Robertson

UPDATE FROM LAST ISSUE: It appears that someone is working on

a 3TS2068/5PECTRUM interface. Apparently it is àa lot more complicated than simply changing bus configuration. Aerco (Austin Texas) is marketing a great looking TS2068 Disc System. Bottom line is 508.00 (US) for this complete 2 drive system with cabinet and 64k Ram/Bk Rom onboard. For details see their advert. in latest issue (HII) of T-S Horizons.

U.K. NEWS! Two interesting items gleaned from recent issues of Your Computer; а) a survey of 23,000 Open University students with home micros indicated that Spectrum was no. 2 with 15% and that the ZX81 was no. 3 with 11% (of further interest was the face that the CBM 64 was 4th with 6% and the Apple was tied with the Т19 at 4%), b) a comparison between the BBC and the QL which makes us dedicated Sinclair types cringe a little, as the BBC comes out ahead.

T82068: There are several enterprising programmers. advertising enhancements for the TS2050 Modem MTERM software which received such bad reviews because of the Documentation (ог rather,the lack of it). Did you know that the Spectrum version of Tasword II does NOT WORK with the TS2068 with Spectrum Rom. It does not print out! Conversely, during a conversation with 21st Century Electronics I was advised that a 152068 program which worked with the Spectrum Rom (inside a 152068) did not work on the Spectrum. Verrry interesting.

TS 1000: If there still are some dedicated users out there, I suggest that if you want to purchase hardware items still advertised, that you get cracking. They will not be around forever. There are quite a few items available in the П.К. or from Integrated Data Systems (who carries most of the U.K. items). John Oliger is still offering his Hi-Res with colour kit.

SPECTRUM ROM: 0+ all the games reviewed I must say that SABRE

WULF by Ultimate is the best (in my opinion that ix). Two others deserve honourable mention, Jet Set Willy and Kokotoni Wilf. All three make good use 0+ graphic capabilities, The following languages are available for the Spectrum: Forth (several versions), Beta Basic (enhanced Basic), Pascal, C, Micro Prolog,

Logo and Lisp.

MAIL ORDER FROM U.K.: Most U.K. prices quoted in magazines

are "Inclusive" or "Inclusive of VAT". VAT is a value added tax of 13% on top of the item price. Therefore deduct VAT from the quoted "Inclusive" price (multiplier .885) and add appropriate postage. On cassettes add approx. (2.00 each, to a total of 4, then add £0.75 for each additional. For larger items always add a тіп. of £5.00 to £7.50. Airmail costs are incredible, і.е. р £7.50 for a £mall item (if larger than standard envelope size).

COMPUTERS AREN'T HUMAN Most humans use the decimal system, which consists of ten digits (0, 1, 2, 3, 4, 5, 6, 7,,8, 9), because humans have ten fingers. The computer does not have fingers, so it prefers other number systems instead. Неге they are....

5 | BINARY Look at these powers of 2: 29 =1 21 = 2 22 = 4 23-8 2" = 16 25 » 32 28 = 64

Now try an experiment: pick your favorite positive integer, and try to write it as а sum of powers of 2, For example, suppose you pick 45. You can write it as 32+8+4+1. Suppose you pick 74; you can write it as 64+8+2. Suppose you pick 77; you can write it as 64+8+4+1. Every positive integer can be written as a sum of powers of 2.

Let's put those examples in a table: ORIGINAL WRITTEN AS A SUM DOES THE SUM CONTAIN...

. NUMBER OF POWERS OF 2 647 32? 16? 8? 4? 2? 1? 15 52+8+4+1 no yes no yes yes no yes

174 644842 es no no es no es no es

64+8+4+1 es no то es yes no To write those numbers in the inary зузфет, replace "по" by 0 and "yes" by 1:

DECIMAL SYSTEM BINARY SYSTEM

45 or simply 101101

/ г 0

The Деетта,. Bye ber uses the digits 0, columns: thousands hundreds tens units For example, the decimal number 7105 means "7 thousands + 1 hundred + 0 tens + 5 units". The binary system uses only the digits 0 and 1, and uses these columns: sixty-fours thirty-twos sixteens eights fours twos wits ‘For example, the binary number 1001101 means "1 sixty-four + 0 thirty-twos + 0 sixteens + 1 eight + 1 four + 0 twos + 1 unit"; in other words, it means seventy-seven. In elementary school, you were taught how to do arithmetic in the decimal system. You had to memorize the addition and multiplication tables: DECIMAL ADDITION DECIMAL MULTIPLICATION 3 4 5 6 7 9 0 1 2 4 5 6 7 8

» 2, 3, 4, 5, 6, 7, 8, and 9 and uses these

?

3 0 5

юы C UO Rt N PB mw CS i = C4 bor

^ атп 9 10 11 12

oO) C Un i LA Jom C

0 0 1 2 5 4 5 6 7 8 9

2 09 МС CD hut! ©

10 11 12 15

In the binary system, the only digits are 0 and 1, so the tables are briefer: BINARY ADDITION BINARY MULTIPLICATION | 0

0 1 i 1 0 ofo o 11100 &босацзе доо is witten 110 1

"10" <n binary If society had adopted the binary system instead of the decimal system, you would have been spared many hours of memorization!

Usually, when you ask the computer to perform a computation, it converts your numbers from the decimal system to the binary system, performs the computation by using the binary addition and multiplication tables, and then converts the answer from the binary system to the decimal system, so you can read it. For example, if you ask the computer to print 45+74, it will do this:

45 converted to binary is 101101 *74 converted to binary is *1001010 Eu 1110111 converted to decimal is 119

Dame usd

The conversion from decimal to binary and then back to decimal is slow. But the computation itself (in this case, addition) is quick, since the binary addition table is so simple. The only times the computer must convert is during input (decimal to binary) and output (binary to decimal). The rest of the execution is performed quickly, entirely in binary.

You know fractions can be written in the decimal system, by using these columns: units point tenths hundredths thousandths

For example, i2 gun be written as 1.625, which means "1 unit * 6 tenths * 2 hundredths *

8 5 thousandths".

To write fractions in the binary system, use these columns instead: units point halves fourths eighths

For example, 12 is written in binary as 1.101, which means "1 unit * 1 half + 0 fourths + 1 eighth". You know i is written in the decimal system às 0.3333333..., which unfortunately

s : i : : 1, : never terminates. In the binary system, the situation is no better: zis written

as 0.010101.... Since the computer stores only a finite number of digits, it cannot 1 EST : store = accurately—it stores only an approximation.

A more distressing example is т. In the decimal system, it's .2, but in the binary

system it's .0011001100110011.... So the computer can't handle = accurately, even

though a human can. Suppose you enter this on your ZX-81l computer:

PRINT "MY FAVORITE NUMBER IS ";4.001-4

The computer will try to convert 4.001 to binary. Unfortunately, it can't be con- verted exactly; the computer's binary approximation of it is slightly too small. The computer's final answer to 4.001-4 is therefore slightly less then the correct answer. Instead of printing MY FAVORITE NUMBER IS .001, the computer will print MY FAVOURATE NUMBER IS .0010000002 . Other computers come up with numbers like .000999987 ,

To test your 7Х-81'5 accuracy, try 4.0001-4, and 4.00001-4, and 4.000001-4 etc. you might be surprised at its answers.

ALL 2 nd Zrectrum prearams TERRE REN Е _ эге i ÁJrecorded an tape if PROGRAMS STRUCTURE one n2 e бєгїп. These FRETA am ве Figure zhows some Of the ^2 iproaram) Easit tion of a Prearam. ALL EN TELES] of the сагат would be on tape oy т SBE iii fated ih Fiaufre 2. IHE CODE (butes) This i typical G-section 5 ргоага ith basic, screen and Basic Programe мша! | iust tade. LE Line ЭЙ whith i5 the have a bazic section but save | » FLL programs „Жш. С machine code rroarzinz have 2 ar a LWA MS WE а SANE line, ; 8 sections, These could include this o! the basic is saved bu | the bazit Section, maybe a Em diee "T 7 | Ае and at Least one code ZOUE "example" LINE 20 == : ECU This means that whem the saved | REDATE is loaded, it ш \ automaticatlu ag to Line AO. | herefore ine ZU if cattle & ! PERDER autoestart Line CF S bon ts | мег sertian nn tape it Line instructs ta L "s" геа а bs a header. This is SCREEMS so that the. screen wilt the short part that loads when load while the tape is still the border shows blue & red running, Then line 39 will Гоар stripes. After a header has mc" which are the machine Code Loaded, the.title of the bytes. This is the tast section section mitt Usually appear on fo be Loaded zo line 40 PRINTS screen, Besides the title, the а message to stop the tape header also Loads im the length Plauer, and starting address of the eection, The rest of the program is then ExXECULEd and somewhere in the basic there will be an instruction to access the machine code that was previousLu Loaded. (This if done With the USR command), As the header af gath section uas loaded. the screen would have disrigsued Figure 3, however, a SCREENS would cover up part FIGUGE of ait.

LORD "s" SCREENS LORE "me" CODE

FIGURE 2

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PLS : PRINT "Stop Tape"

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(Basic Program)

STOP

FIGURE 3

SAVE “Еехамтр|е” LINE 20: "s" SCREENS: SALVE "mc'"CODE

STOP Program: example

bytes: Е

bytes:

me

зи.

г шоп t i ace or the basic wie L sin а TAVE line рне ki xeu and not know where the LUR CODE su UR Mer n iD pot erase this from youi compzter Stree 1 То LL these Problems, we аж us isl utility program Immiiistziu atop the tape tt iz ия 2 Load a header thi: point. ы йы ari it and it gives us кат om ali the required information. ———— One such utility is called Е ны "Header". TO USE it we first р ое load it in and just Follow the = . directions on the screen. The SAVE "=" header Gf each section is шы Е loaded in with "Header" and we HOTE 3 =f | Сап read the needed info on the АРЕ sereen andor iet the printer fis: E ОИ Therefor saved it SAVE "2" CODE 16364,6912

6. LORD in the last section (machine code) from the LET’S TRY IT Original tape With:

LORD "" CODE

1, We Mill make = back-up oF ihe proaram in Figure 1, The Ts Gave Fi: rode and indicat First ziep is te Ghtain the the sddrezz it is to be pui following information amd the Length or it. +Наме of esch section, ZAVE "mc" CODE 40000,1208 &Huto-ztart iine GF basic, Stapi address of each code In the Sample the 48000 is E£&ciion, and fus Je TE ар of En | code ап 2ай is е numbe; xLenath of each COde section Se Rule Cono 1s e ERE If this cannot be recadillu must be included Whenever obtained bu looking for the faving code, fgve Line in the basic, then YOU must use a special $. If the program has more utilitu such as "Header". sections just repeat the E procedure for the extras,.ai 2. How Load in only the basic if there are fewer, omit section of the Proaram in those. How you mag Wish to one of tuo ways., Ome Way is verify everything using: te LORD "" and BREAK when it [n has Loaded the first section WERIFY "" In zome Programs чои may | na Е арїє io BEZAR, For . io check the basic and: these uou myst toad them "m using: НЕРСЕ "". This will VERIFY "" CODE Cauze & break automatically . at the end of the first fhe code. vou can section. Tru to stop the У the SCREENS за tape player right at the end over at when Gf this Bection ЕС that it is positioned at the start Gf the second section. 3. This bassiC Can now be saved onto your back-up tape bu: НЫЕ "example" LINE 20

PROGESHH ING TRICKS us БЕ using the Sane ThE titi Of the basic program E Griginet unless MILL aiu dz Frint on screen = the proaram When 115 header is logged, but nasmez. the titie of i OF OL Lona ЕС: ИЕ if = times not =. 2 in doubt whether shown, This i done bu makina ЕС: ПМ is Е agren the ink Sand paper the rise or Пе code, Load it colour before that section With: LOADS "" CODE loaded. Obtain the hidden title . bu the wee of "Header", =. £times uou will not need use the Header Utility. When the basic section if 2 Programs have all the loaded and you with to BREAK etsay info in 8 Save. the loading process at the end = in the basic section, Of the section, uou may ae a crash of it mau keep an 4. When faving a screen, it loading. This trick is done by ИНЕТ БЕ Present on the Tu a FORE in ThE suto-start Line Screen nr it Will Mot save, Or Бч the ON ERR command, : Overcome this problem bu load- 5. If the basic has а save Line ind the basic With the MERGE uot can GOTO this Line te Command. Save all sectione but Note | #4 applies. When Saving more Sometimes there is a blank area than one section by using Of tape between sections. This the fave Ling, be ready ta WoUld be needed for the basic Press a key when Prompted. 46 do something before the Line | that loads the next section, $. Mote that throvahout this For €. amt LE, the “Upload Оса" Srticle, I have used the Program dots a short display term "back-up" в: opposed tn ГРИН СЕ ЕЛ the basic and 5 "copy", Even though we are thé Machine code. Be sure to desting With Making as copy ameert this came tenath СЕ nr cupLicate nf an original tlàn! im your baàtk-UuP. YOU can Program, ihe term "back-up" determine this lenath bu timina haz 3 more legat fring to jt! st or With the tape counter, Integrated Data Systems 30 Brookmount Road, Toronto, Ontario IL ЗМІ 416-443-5518 (Answer-phone)

Please note that we have moved and that the above is our new address and phone number. We still have а full catalogue of ZXB8':/TS:1000 items although this is decreasing all of the time.

We have publication rights to software from Ezra Group II, Hargrave, Woods plus other authors under our own name. We alsn believe that we are the Only company in North America selling Centronics and RS232C Interfaces that are port mapped not memory mapped, The Dual Centronics is $89 and the Dual RS232C is $149.

Both come with

along with evailable.

2958’ s can all

EPROM Poards

software on and some of

$24.96. TS1829'5,

be provided

on consignment,

We scrept wriless there printsez

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ere books where it is +5, or

nr modems.

tape but we can alse provide on EPROM the most useful utilities We also carry books such as Mastering MC at and RDM Disassembly ARB at

$15.99 TS RAMS 2949? and

Piss some used equipment that we sel]

2

or cheques and charge 1,50 PRH/order

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USE OF THE 7 IN FUNCTION ju G Е Chambers

It is sometimes desirable to be able to use tuo keys at ihe _ same time, Many games could be improved with this Capabilities On the Т52958 this 1% BOGS sins through the use of ine 'IH function.The fol lowing Table Я, and Ftch-a-Sketch demonstration program till illustrate this possibility.

IN

Зот BR SH H N E 49158 ENTER L К. a H 57340 Р ü

e 43486 à oe

> a к к Te л ad E [Ly

5 РЕМ

T

an ETC KA-SKETTH ТУРЕ of drauing routine ta illustrate the USE oF the IN runct the Т52 058 Б БЕН _ T REM Bu G а RE р = а REM Use key a rar cur А lise КЄ Ноа: ce H 18 LET x=125: LET =a E 2A IF IN 54510 -30 AND yilve TH EH LET yeuystl == зв IF IN 55022 =за AND yuri THEN zu-:

ETGS42 =ЗА AND imma TH 7348 2228 ANG xii THEN SALES 4:31 THEN GO 305 aa хуч п ze гей: LET c IH imc t-Cc/2: LET parti: IF c п TO ва о 14а _ _ ۶ HEEYHE:"" THERM Go ТО Б mh a

"m Ti D (n 1-4 з 1 п m ti

uh to ЕГЗЕЕ а tar = 3 bulk eras af away should it b other tapes? Arte = number of EXPE oncluded that ther = major cancern РОГ rasure of prog img, is а List or t {t= Which did not ect on a short prz- aram. x Hoving s head-demagni fier around the tape,

+ Pep "ап a e

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x u antact with colour hile it was turned

m fuk a

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tape under a telephone it rang 5 times.

SCREEN COPIES on the inter with tape in With printer.

+ Held tase about 1 (ONE) inch From bulk tape eraser while turning eraser orf & оп and mawvina tape around!!!

Я kargar zresnker 3 t [ e.a!

B nr.) would pro erase the

(rogram, Likewis ing the

tape within 1" û bulk

eraser ji: “Goodby aram": eyen if the eras switched on & OFF nce Н: this if nat cons = a tal.

Sa why b baut. erasing = program? The real sguzeée ror Lost ora careless finger б Button.

41 T1

Du

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BOTTOM

SIDE B

ZX - 8l

ROMCS

TOP

7 МЕЛ Hardware Meus by Peter N°Mullin for ТЕ. С. 27/85 #1 in a Series for the ADVENTUROUS, COMMITTED 7X8! Owner.

took advantage of the great price on GLADSTONE 64K RAM packs

isable the 8K-16K block, so they can use

some of the many peripherals which are mapped to that area. To this end,

I have drawn an improved schematic of the 664К for reference, and written

an article, with documented schematics, outlining the necessary procedures. А simple address decoder and MREG NOT gating does the trick.

with options depending on required switching flexibility. In fact, although

not mentioned in the article, this method could be used to selectively

disable ANY block of memory between O & 64k! |

The details are too involved to relate here, sa I have placed copies

of the project manual in the CLUB LIBRARY: it is available there

for those who require it.

Many who have expressed the need to d

or info on using the cheap but nifty EXCELTRONIX 5" Greenscreen monitor. (I just found the file:) | |

The problem is with the supplied sync separator, NOT with the monitor itself. My solution involves using the partial sync-separation provided by the | Random Access VIDEO INVERTER circuit, which was published as a construction

project in Computers k Electronics, May 'B83 issue. А5 with the G564K project, l will place full details in the LIBRARY as soon as I can prepare the material.

Apologies to those waiting f

erm

Т am composing this text on my 64K 7Х81. outfitted with a surplus Appl lone keyboard, using Word Sinc II. Text is output on an EPSON MX-BO printer, іа the EPROM SERVICES Centronics interface and software driver, hich 1 recently purchased fron Integrated Data Systems. ft 4u encouraging to report that MEMDCALC, and ZX PRO-FILE (Centronics JE чето) both print out just fine with the EPROM SERVICES I/F and software. utput of the printer CTRL and «ESC- codes, so valuable ín wordprocessing,

з a sticky subject, though. I BREAK from WSII menu, t LFRINT At to do it here.

I am currently awaiting replies from both P. Hargrave and EPROM SERVICES regarding WSII.4 compatibility. Things seem promising, so I^11 keep you posted.

My final topic for this issue is the most exciting. I recently received documentation on the long-awaited ZXB1 Video Upgrade project, created by John Dliger, 11601 Whidbey Dr., Cumberland, IN 46229.

The following features should make you sit up and take notice: 1) SLOW mode is 5.5X normal speed. i.e. same as 2068. Some M/C games

run TOO FAST, and arcade-speed games in BASIC become possible! FAST mode, as usual at 6X normal SLOW speed, is BLINK-FREE! 2) You get COLOUR VIDEO with UPPER and lower case on screen, as an alternative to inverse characters. Colour control is equiv. to 2068. з) Machine code can now run anywhere in 464K, with free use of the IX register, and schemes using vectored hardware Interrupts may be supported. 4) System is completely transparent to existing software. 5) Display File CRASHES are NO HORE!

The project consists of two circuit boards. one for the TMS9718 Video Display Processor (which supports SFRITE graphics) and 16K Video RAM.

The other circuit board holds an enhanced(i.e. display routines rewritten) versian of the ZXB1 ROM, which it overrides. А Motherboard оғ" cable is required. Mr. Oliger sells both boards, and all parts except the VDP and it s crystal

for $48.95 U.S. (Quick! Where's my checkbook?) Write to him for details. |

Discoveries like these make the AERCO Disk System for the ZX81 seem more attractive all the time to a hardware addict like me. But that's for another discussion. Ho рух Com pat Хр"