Type-In Listings | Code Like It's 198x

In January 1984 Computer & Video Games printed a game for the Dragon 32 that began REM ROAD RUNNER BY PHILIP OLIVER. Anyone who wanted to play it had to type it in, line by line, from the magazine. For Philip and Andrew Oliver it was their first published game, and the £50 fee went towards a BBC Micro. They had taught themselves to program by changing other people’s listings, and within a few years they were writing Dizzy.

A type-in listing was a complete program printed in a magazine or book for readers to key into their own computer. Before most people had a disk drive or a modem, it was the cheapest way to get new software: the magazine cost less than a game, and the program was free once you had typed it. It was also, whether readers meant it or not, a programming lesson. Typing a game in meant looking at every line of it, and the typos that followed taught debugging.

Where the listings came from

Printed programs were older than home computers. David Ahl’s 101 BASIC Computer Games, first published by DEC in 1973, was advertised in 1976 as “a collection of 101 games in BASIC, each one with a complete listing, sample run, and write-up”. When cheap home computers arrived at the end of the 1970s, magazines filled pages the same way, and much of what they printed came from their readers.

The British monthly Your Computer ran a “Software File” in 1981 that gave readers “the opportunity to have your programs, ideas or discoveries published”, asked them to “double-check your listings before sending them”, and paid £6 for each one used. By 1983 it paid £35 a printed page for articles. Sinclair User paid £10 for each program it printed from its first issue in April 1982, and from January 1985 £20, with £50 for a “star program”. Its publisher, ECC, launched a whole magazine of listings the same spring, Sinclair Programs, whose first issue in May/June 1982 offered more than forty programs for the ZX80 and ZX81, from Chasvaders to Ohm’s Law, again at £10 a program. It lasted until 1985.

In America COMPUTE! printed listings for several machines in each issue, and COMPUTE!’s Gazette did the same for the Commodore VIC-20 and 64 from July 1983. In Britain Marshall Cavendish sold INPUT as a partwork in 52 parts from 1984, a programming course whose listings covered the Spectrum, Commodore 64, BBC Micro, Acorn Electron and Dragon at once, with symbols to mark the programs and lines meant for each machine.

Typing it in

The Usborne computer books brought the same idea to children. Computer Battlegames and Computer Spacegames, by Daniel Isaaman and Jenny Tyler (1982), printed each game for the ZX81, many of them short enough for its 1K of memory, with the lines to change for the Spectrum, BBC, VIC-20, TRS-80, Apple and Pet printed underneath, each marked with the machine’s symbol. Write Your Own Adventure Programs (1983), by Jenny Tyler and Les Howarth, followed. Their advice on typing in is a good picture of what it involved:

You may find it easier to get someone to read the program out to you while you type it in. Don’t forget to explain that they must read every comma, full stop, bracket and space and differentiate between letter “O” and zero, FOR and 4, and TO and 2.

A mistake could be yours or the magazine’s. Listings were either photographed from a printout, which could shrink them to illegibility, or re-typed by a typesetter. “Copy typists were untrained for the character-perfect accuracy required for listings,” Simon Goodwin, who had more than a hundred listings published, told Retro Gamer in 2004, “skipping sections when the program seemed (necessarily) to repeat itself, mistyping crucial but cryptic numbers like POKE addresses”. He remembered one art editor “picking lines from a listing apparently at random and scattering them through a long program like cross-headings”.

So corrections became a regular feature. COMPUTE! printed its fixes on a page called “CAPUTE!”. INPUT asked readers who wrote in to give “the Part No., page and line where the program is rejected”, and added: “please do not telephone”. Your Sinclair’s troubleshooting column in March 1986 explained that its printer had once turned hash signs into pound signs and was now printing “a sort of curly closed bracket that isn’t”, so readers should type a hash wherever they saw a character they could not identify. In July 1984 C&VG printed a machine-code listing of Automata’s Olympimania; two issues later it admitted it had given the wrong starting address.

Checksums and proofreaders

Machine code was the hardest case. Games that needed speed came as pages of numbers in DATA statements or hexadecimal, and one wrong digit could crash the computer with no error message to say where. Magazines answered with programs that checked the reader’s typing as they went.

COMPUTE!’s program editor, Charles Brannon, wrote two of them. “The Automatic Proofreader” first appeared in COMPUTE!’s Gazette in October 1983, and COMPUTE! printed it for the VIC-20, Commodore 64 and Atari in March 1984. It sat in memory while the reader typed a BASIC listing, and after each line it showed a checksum, a number or pair of letters worked out from every character in the line, to compare with the one printed beside that line in the magazine. The March 1984 issue also carried MLX, “a new way to enter long machine language (ML) programs with a minimum of fuss”, for the Commodore 64; an earlier MLX for the Atari and Commodore 64 had appeared in December 1983. Each MLX line held “six actual data numbers plus a checksum number”; if either was wrong, “the computer rings a buzzer and prompts you to reenter the line”. It would not accept a number greater than 255, and it let readers save a half-finished listing and come back to it, because “you don’t have to enter the whole ML program in one sitting”. There was a catch: both checkers were themselves listings, and had to be typed in carefully without one.

British magazines did the same. Your Sinclair printed a hex loader that asked for an address, eight bytes and “the checksum - that’s the number after the equals sign at the end of each line”. As late as November 1994 Amstrad Action printed a four-letter code at the start of every line of its type-ins, for its “TypeChecker” program to match.

A rung on the ladder

Listings were the bottom rung of publishing, and everyone knew it. Sinclair User, advising readers in August 1985 on selling a game to a software house, said: “There is no point sending in a game only good enough for a magazine listing. The software house will not even look at it.”

But plenty of programmers started on that rung. The Oliver twins began by changing type-ins on a ZX81 before their Road Runner listing was published. Robin Muir, who wrote music for the Spectrum conversions of Platinum Productions, told CRASH in 1985 that he had started out on his father’s ZX81, “typing in listings and the like”. The bedroom coder entry follows where that road led.

Decline

The games magazines that grew fastest in the mid-1980s did without listings. In its second issue, in March 1984, CRASH told a reader: “Program Listings were never, ever on the agenda for CRASH! There’s just not the room anyway.” It was built around reviews of commercial games instead, and as those games grew larger and faster, a listing that could compete with them had to be pages of machine code.

Cover tapes removed the typing. The January 1987 Amstrad Action came with a cassette that let readers “ENJOY our greatest-ever type-ins without typing in!”, and in 1989 Commodore Disk User advertised itself with the question “Do I want my programs ready to use without typing in endless listings?” Listings did not vanish at once: Amstrad Action was still printing type-ins, and its TypeChecker, in 1995.

The Usborne books had a second life. In February 2016 Usborne put its 1980s computer books online as free PDFs, and their listings could be typed in all over again.

Sources

BYTE issue 11, July 1976: Creative Computing advertisement for 101 BASIC Computer Games.
Your Computer, October 1981: “Software File” (£6 for each contribution). March 1983: contributors’ guidelines (£35 per published page).
Sinclair User issue 1, April 1982: contributors’ notice (£10 for each program printed). Issue 34, January 1985: letters page (corrections; “paying £20 for each program published, and £50 for star programs”). Issue 41, August 1985: Clare Edgeley, “Programs for Profit”.
Sinclair Programs issue 1, May/June 1982 (ECC Publications): contents and contributors’ notice (£10 a program). The last issue is dated September 1985.
Computer & Video Games issue 27, January 1984: “Road Runner” by Philip Oliver, for the Dragon 32. Issue 35, September 1984: correction to the July Olympimania listing.
CRASH issue 2, March 1984: letters page (“program listings were never, ever on the agenda”). Issue 21, October 1985, p. 124: Graeme Kidd’s profile of Platinum Productions (Robin Muir).
COMPUTE! issue 46, March 1984: Charles Brannon, “The Automatic Proofreader” (p. 60) and “MLX: Machine Language Entry Program for Commodore 64”; Readers’ Feedback notice on corrections and the CAPUTE! page.
COMPUTE!’s Gazette vol. 1 no. 1, July 1983.
Daniel Isaaman and Jenny Tyler, Computer Battlegames and Computer Spacegames (Usborne, 1982): “About this book” and “Typing in the programs”. Jenny Tyler and Les Howarth, Write Your Own Adventure Programs (Usborne, 1983).
Your Sinclair issue 3, March 1986: “Troubleshootin’ Petrovitch” (hex loaders, checksums and the printer).
Amstrad Action issue 16, January 1987: cover. Issue 110, November 1994: type-ins and TypeChecker. Issue 117, June 1995: type-ins.
Your Commodore, November 1989: Commodore Disk User advertisement.
Retro Gamer issue 5, 2004: Andy Krouwel, “Basic Instinct” (Simon Goodwin on typesetting and published listings).
Edge issue 105, Christmas 2001: interview with Philip Oliver; see the Oliver twins entry.
Wikipedia, “BASIC Computer Games” (web, secondary): the 1973 DEC edition. https://en.wikipedia.org/wiki/BASIC_Computer_Games
The Register, 9 February 2016 (web, secondary): “Ready for a nostalgia kick? Usborne has put its old computer books on the web for free”. https://www.theregister.com/2016/02/09/usborne_programming_books_now_free/
COMPUTE!’s Gazette issue 4, October 1983: the first “Automatic Proofreader”. COMPUTE! issue 43, December 1983, p. 216: MLX for the Atari and Commodore 64.