<P> Processor clock rates were typically 1--2 MHz for 6502 and 6809 based CPU's and 2--4 MHz for Z80 based systems (yielding roughly equal performance), but this aspect was not emphasized by users or manufacturers, as the systems' limited RAM capacity, graphics abilities and storage options had a more perceivable effect on performance than CPU speed . For low - price computers the cost of RAM memory chips contributed greatly to the final product price to the consumer, and fast CPUs demanded expensive, fast memory . So designers kept clock rates only adequate; in some cases like the Atari and Commodore 8 - bit machines, coprocessors were added to speed processing of graphics and audio data . For these computers clock rate was considered a technical detail of interest only to users needing accurate timing for their own programs . To economize on component cost, often the same crystal used to produce color television compatible signals was also divided down and used for the processor clock . This meant processors rarely operated at their full rated speed, and had the side - effect that European and North American versions of the same home computer operated at slightly different speeds and different video resolution due to different television standards . </P> <P> Initially, many home computers used the then - ubiquitous compact audio cassette as a storage mechanism . A rough analogy to how this worked would be to place a recorder on the phone line as a file was uploaded by modem to "save" it, and playing the recording back through the modem to "load". Most cassette implementations were notoriously slow and unreliable, but 8" drives were too bulky for home use, and early 5.25" form factor drives were priced for business use, out of reach of most home buyers . An innovative alternative was the Exatron Stringy Floppy, a continuous loop tape drive which was much faster than a datacassette drive and could perform much like a floppy disk drive . It was available for the TRS - 80 and some others . A closely related technology was the ZX Microdrive developed by Sinclair Research in the UK for their ZX Spectrum and QL home computers . </P> <P> Eventually mass production of 5.25" drives resulted in lower prices, and after about 1984 they pushed cassette drives out of the US home computer market . 5.25" floppy disk drives would remain standard until the end of the 8 - bit era . Though external 3.5" drives were made available for home computer systems toward the latter part of the 1980s, almost all software sold for 8 - bit home computers remained on 5.25" disks; 3.5" drives were used for data storage . Standardization of disk formats was not common; sometimes even different models from the same manufacturer used different disk formats . Almost universally the floppy disk drives available for 8 - bit home computers were housed in external cases with their own controller boards and power supplies contained within . Only the later, advanced 8 - bit home computers housed their drives within the main unit; these included the TRS - 80 Model III, TRS - 80 Model 4, Apple IIc, and Commodore 128D . The later 16 - bit machines such as the Atari 1040ST (not the 520ST), the Commodore Amigas, and the Tandy 1000s did house floppy drive (s) internally . At any rate, to expand any computer with additional floppy drives external units would have to be plugged in . </P> <P> Toward the end of the home computer era, drives for a number of home computer models appeared offering disk - format compatibility with the IBM PC . The disk drives sold with the Commodore 128, Amiga and Atari ST were all able to read and write PC disks, which themselves were undergoing the transition from 5.25" to 3.5" format at the time (though 5.25" drives remained common on PCs until the late 1990s, due to existence of the large software and data archives on five - inch floppies). 5.25" drives were made available for the ST, Amiga and Macintosh, otherwise 3.5" based systems with no other use for a 5.25" format . Hard drives were never popular on home computers, remaining an expensive, niche product mainly for BBS sysops and the few business users . </P>

When was the first computer offered to the public and what was its name