Tandy/Radio Shack Advert - 18th August 1983
From Personal Computer News

"New TRS-80 Model 4 - from Tandy"
Proving that sometimes the same model can live on seemingly for ever, at least in name only, is this advert for the TRS-80 Model 4. The original TRS-80, one of the "1977 Trinity", had been launched 6 years before, and this model bears little resemblance to it, in the same way that a Mk. 4 Vauxhall Astra is nothing like the awesome Mk. 1. Interestingly, given that this was a computer aimed more a the business market (into which the iconic IBM PC had been launched in 1981), the amount of memory available on the basic model is still only 16K and was still running an 8-bit Z-80a processor (the IBM provided between 16K and 256K and a 4.77MHz Intel 8088). There was also a "conversion kit" available, which enabled Model 2 disk-system owners to upgrade their box to a model 4. The price of £749 is about £3,000 in 2011 terms.
During this period, commentators reconned that Tandy seemed to be producing a new machine every week. In fact in the same week as this advert, Tandy's TRS-80 Model 12 was already in the shops. This was a "sub-IBM PC-class" machine with 80K RAM, one or two built-in 1.25Mb floppy disk drives and a detachable keyboard. With two floppy drives it cost £2,999 (about £10,000 in 2019). Adding a 12Mb hard disk added the same again, i.e. another £2,999 (£10,000)[1].
Sources
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