"an ideal toy for youngsters who want to become acquainted with the computer world. It is responsive, cheap, and very easy to use". Billy Garrett of Byte, who already owned a ZX80, complimented the Timex/Sinclair 1000s manual (although he regretted the removal of the British original's humour), the "state-of-the-art circuitry", and the BASIC for being "remarkably powerful" despite the small ROM size. He concluded that "the major use ... will probably be for learning about BASIC or computers in general. [It] has limited expansion capabilities, and the keyboard is too small and cramped for any serious work". David Babsky described the ZX81 as "a wonderfully brainy little micro which won't let you waste your time and make a fool of yourself". In a comparison between the ZX81 and IBM PC published in Which Micro?, he commended the ZX81's user-friendliness and its on-the-fly syntax checking of BASIC programs, which he described as "the feature that I, as a newcomer to computing, want to see incorporated into every micro." Peripherals and software The success of the ZX81 led almost immediately to enthusiasts producing a huge variety of peripherals and software. Clive Sinclair was "amused and gratified" by the attention the machine received but other than what Clarke described as "a few remarkably poor programs on cassette", his company made little effort to exploit the demand, effectively ceding a very lucrative market to third party suppliers, a decision that undoubtedly forfeited a lot of potential earnings. W.H. Smith, for instance, was able to exploit a peculiarity of the ZX81; owners found that technically obsolete low-fidelity mono tape cassette recorders worked better as storage devices than higher-quality music systems. Smith's purchased cheap "shoebox" cassette recorders in the Far East and sold them with the W.H. Smiths logo as "data recorders". Over 100,000 were sold in 18 months. Sinclair released only two official peripherals for the ZX81, a 16 KB RAM pack (actually the same one previously released for the ZX80, but rebadged) and the ZX Printer, both of which plugged into the edge connector at the rear of the ZX81. They retailed at a launch price of £49.95 each but both had notable flaws. The RAM pack was top-heavy and was supported only by the edge connector. It had a habit of falling out of its socket at crucial points and crashing the ZX81, losing anything that the user had typed in. Users turned