Date: February 1982
Volume: 3
Issue: 2
Articles
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Sinclair Discontinues Tech Info LineNigel Searle of Sinclair just announced that Sinclair would no longer staff their technical information line in Boston.
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Edge Connectors AvailableZX80 ZX81 Kopak Creations of New York now offers 46-pin edge connectors for ZX80/81s.
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Nonauthorized ZX81 Sales and ServiceZX81 National Electronics III of Concord, TN, has become a nonauthorized reseller of new assembled ZX81 systems.
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6K RAM AdditionZX81 Hardware project Frustrated by the limitations of 2K RAM, Jim Graham of Oakham, MA, put 6K “under the hood” of his ZX81. He finds it a comfortable compromise, freeing up the edge connector for I/O use. The wirewrapped module consists of four sockets welded together, needs no board modifications and plugs into the existing RAM socket.
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Surplus Keyboards Plus DirectionsZX81 Hardware project The $20 surplus keyboards from John J. Meshna Jr., Inc., mentioned in the Dec. 81 issue, now come with wiring instructions for ZxX80s.
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Syntax ErrorsZX81 Peter Ulrich, New York, sent corrections for Paul Ezra’s Brownian Motion program (Dec. 81). David Ornstein corrected his New 8K ROM Routine Addresses list (Jan. 82). Jon Passler sent some improvements for his 8K Bar Chart program (Jan. 82) to speed up program execution.
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Translating BASICs -- What Won't WorkZX80 With all the software available for other computers, many ZX80 owners want to convert programs from Microsoft BASIC (used in PETs, Apples, and TRS-80s) to ZX80 BASIC. Sometimes this proves futile due to inconsistencies between Microsoft and ZX80 BASIC.
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Phone Number Word GeneratorZX80 ZX81 Type-in program What does your phone number spell out if changed to letters? A friend’s phone number, 438-5678, spells GET LOST. A bank’s auto loan department answers NEXT CAR.
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Binary Addition and SubtractionThe point to learning how to add and subtract binary numbers is to see how “carries” are generated and what happens to those extra digits.
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The Flags of the 8K ROM ProgramZX81 TS 1000 The ZX81 manual states that the three system variables FLAGS, FLAGX and CDFLAG hold various flags to control the BASIC system. But a study of the 8K ROM program discloses 12 separate flags.
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User Report: Insight's 16K RAM PackZX81 TS 1000 Hardware review At first glance you might ask, “Is that all there is to it?” I opened the shipping box to find a small black plastic case that obviously plugs into the rear of a ZX80/81 or MicroAce computer.
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Moving BillboardZX81 TS 1000 Type-in program This program continuously scrolls up to 23 (and more) lines of characters. Do not print more than 32 characters in any PRINT instruction, such as line 150, or the scrolling will fail.
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DIM as Calculator Sum-to-MemoryZX81 TS 1000 Type-in program DIM arrays can function as a sum-to-memory system found in many calculators. More importantly, it acts as a counter function and can be used where FOR-NEXT loops will not work. Moving Billboard, this illustrates the counter function.
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Solving Simultaneous EquationsZX81 TS 1000 Type-in program This 8K/1K program uses Crout’s reduction to solve simultaneous equations. The number of variables you can use is limited only by your available memory; in 1K this program solves up to 4 equations in variables
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Dear EditorZX81 TS 1000 Sinclair discontinues tech support. Inventory control program sought. Connect full size keyboard to ZX81. Improving ZX80 cooling.
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RAM Decoding for ZX81ZX81 Hardware project Last March we published Al Salt’s plans for adding external RAM to ZX80s. To adapt his Build Additional RAM (SYNTAX 02/03/02) with ZX81s, you can take ne of three approaches. The second two of these plans do not require you to modify the insides of your ZX81.
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Loading Problems with ZX81 KitsZX81 If you have loading problems with a kit ZX81, see if you cracked C10 during assembly. Some machines LOAD fine with 1 (or 2)K internal memory, but not with 16K.
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Nuclear Decay SimulationZX80 ZX81 TS 1000 Type-in program A popular lab exercise uses special dice to simulate radioactive decay. Marked die faces show the decay probability. After shaking and throwing the dice, replace those with marked sides showing with spheres (stable atoms) or dice with different decay probability (radioactive daughters). Use over 200 atoms for a smooth graph. This program throws, examines and…
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Salary Scheduling Cost ComputationZX81 TS 1000 Type-in program This 8K/16K program computes salary schedules for two or three classes of teachers (or other workers). For a two column schedule, enter all zeros for the prompts about the third class (Mast+). At the end of the second column, it will ask if you want another. Enter NO and touch NL. The computer will give…
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Sinclair ZX81 ROM Disassembly Part A: 0000H-0F54HZX81 TS 1000 Book review Ian Logan has disassembled and annotated the ZX81 Monitor, easing your access to the improved 8K ROM.
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8K Memory PEEKZX81 TS 1000 Type-in program This slow but simple program peeks memory 100 bytes at a time. It displays consecutive bytes in 5 columns by 20 rows. Designed for the ZX81, it works with 16K RAM.
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AwariZX81 TS 1000 Type-in program Awari is an ancient African game for two players. Six piles of three stones each are arranged in front of opposing players, with each player’s “home” to the right of the piles. The play consists of taking all the stones in one of the player’s piles and, moving counterclockwise, dropping one stone in each pile…