Early in 1982, a ZX81 owner who wanted to go beyond BASIC had few places to turn. Rodnay Zaks’s Programming the Z80 was thorough, and for some readers heavy going. Toni Baker’s Mastering Machine Code on Your ZX81, from the London publisher Interface Publications, started from the other end: it assumed you knew BASIC and nothing else. Five years later a ZX Computing contributor, David Nowotnik, remembered nearly giving up on Zaks before Baker’s book appeared: “That was my salvation. Easy to read, logically building up knowledge, with example routines to try all through the book.”
Mastering Machine Code on Your ZX81
The book was on sale by February 1982, advertised as 180 pages “of immense value to beginner and expert alike” at £5.95, and £7.50 by the summer. Its cover added, in small print, “or ZX80”. Sinclair User’s reviewer in June 1982 called it “one of the best books” from which to learn machine code, and noted that this was no afterthought: “all through the book she makes a clear distinction between codes for the different machines and ROMs.” It was, the review said, what it claimed to be, a manual that would take someone familiar with BASIC “to the point of making real use” of machine code. Your Computer’s advice column in July 1982 reported “good reports” of it, with Zaks recommended “for further reading”.
It travelled. Reston Publishing in the United States issued it for the Timex Sinclair 1000 and 1500, and in Brazil, where Microdigital sold its own ZX81-compatible machines, a book list in Micro Sistemas offered the English edition in 1983. In June 1985 the same magazine printed a Z80 disassembler whose author had built it on an algorithm from Baker’s book. The first issue of Sinclair User, in April 1982, printed a table of the ZX80 and ZX81 system variables “compiled by Toni Baker”.
The Spectrum book
Mastering Machine Code on Your ZX Spectrum followed at the end of 1983. Interface advertised it under the headline “At last!” as a 315-page book at £9.95, “written by Toni Baker, author of the highly successful ‘Mastering Machine Code on the ZX81’”. John Gilbert, reviewing it for Sinclair User in January 1984, recognised it as an update of the ZX81 book. Most examples were the same, among them a “graffiti” program that displayed the character set and three chapters that built up a game of draughts. The Spectrum edition added longer chapters on printing to the screen and on the Spectrum’s own features, and a long dictionary of the Z80’s instructions that Gilbert thought would make it a reference for every beginner, though of “little use to advanced programmers”. His one complaint was a single assembly listing printed on a ZX Printer, which stuck out “like a sore thumb” among the typeset ones. In 1987 Your Computer was still offering it to readers, for the Spectrum and Spectrum+.
Magazines
Baker wrote for the magazines as well. ZX Computing introduced her in June 1982 as the author of the ZX81 book, “convinced the whole subject is a piece of cake”, with a screen-handling routine and the makings of a breakout game. From October/November 1982 to February/March 1984 she wrote a series there, “Mastering machine code on your Spectrum”, which the magazine introduced as “designed to take you through machine code from its very beginnings to its ultimate conclusions”. The first issue of Your Spectrum, in January 1984, carried “A Toni Baker Exclusive!” on its cover. Over the next two years she was on its contributor list and wrote on speeding up arcade games, the “shadow ROM”, making RANDOMIZE properly random, a sprite designer and, in August 1985, an Interrupt Manager that could run up to sixteen interrupt routines. Readers wrote in about her programs. In March 1984 the magazine told readers they could meet her at the ZX Machine Code Users’ Club in Sittingbourne Town Hall, and that the club’s magazine, Micro Arts, was one of her long-term projects. In 1985 she was writing a “Little Screen Designer” series for ZX Computing, and in February 1987 a feature there on three-dimensional graphics.
Who learned from her
The people who learned from Baker included programmers who went on to sell games. In March 1984 Sinclair User profiled Adrian Sherwin, a 16-year-old Liverpool schoolboy who had already sold four games. With the help of Baker’s ZX81 book “he learned machine code”, before moving on to Zaks. In January 1986, over lunch with Sinclair User, the Mastertronic author David Jones said magazines were where he had learned machine code: “Your Spectrum has Toni Baker, and you’ve got Andrew Hewson.”
Public sources say little about Baker’s life outside these books and magazines, and nothing after the late 1980s.
Sources
- Your Computer, February, March and April 1982: mail-order book lists (180 pages, £5.95); July 1982: reader’s advice column (£7.50, “good reports”); August–November 1982: Timedata advertisements (£7.50); December 1983 and January–May 1984: Interface Publications advertisements for the Spectrum book; April–December 1987: readers’ book offer (“Spectrum and Spectrum +”).
- Sinclair User issue 1, April 1982: system variables table “compiled by Toni Baker”; issue 3, June 1982: book review (publisher Interface, 44-46 Earls Court Road).
- ZX Computing, June 1982: “First steps in machine code”; October/November 1982 to February/March 1984: “Mastering machine code on your Spectrum” (part one, October/November 1982; part seven, December 1983/January 1984; “the last part”, February/March 1984); June 1985: “Little Screen Designer”; February 1987: Baker’s 3D graphics feature and David Nowotnik’s recollection.
- Sinclair User issue 22, January 1984: John Gilbert, “Computer facts are made easy for beginners” (review of Mastering Machine Code on Your ZX Spectrum).
- Your Spectrum issue 1, January 1984 (cover); issue 2, March 1984 (contributors, the ZX Machine Code Users’ Club); issue 3, May 1984; issue 5, July 1984; issue 10, December 1984/January 1985; issue 17, August 1985 (Interrupt Manager); issue 19, October 1985 (readers’ letters).
- Sinclair User issue 24, March 1984: profile of Adrian Sherwin; issue 46, January 1986: “Hit Squad” lunch with Mastertronic (David Jones).
- Micro Sistemas no. 26, November 1983: bookshop advertisement; no. 45, June 1985: disassembler listing based on Baker’s book.
- Toni Baker, Mastering Machine Code on Your Timex Sinclair 1500/1000 (Reston Publishing), catalogue entry at timexsinclair.com (web, secondary). https://timexsinclair.com/book/mastering-machine-code-on-your-timex-sinclair-1500-1000/