hard-sector 5 1/4 disk

see below, plz. Dick ----- Original Message ----- From: "Sellam Ismail" <foo(a)siconic.com> To: <classiccmp(a)classiccmp.org> Sent: Tuesday, November 06, 2001 1:57 PM Subject: Re: hard-sector 5 1/4 disk You may well be right about the timing, but the timing isn't the point. I'd suggest you look in the old BYTE mag's (I've given all my useable ones away by now) for the ads from Apparat, a Denver vendor of accessories for TRS-80 and Apple systems. They were a client of mine and the FD subsystem they offered for the TRS-80 was, as I recall, on the market at holiday time in 1979-'80. I'm quite sure Apple had diskette drives out by then, since I got my own (8") drives for my homebrew 6502 setup in '80. That was my first contact with the TRS-80 after-market, but it seems to me that the TRS-80 came out in '78 and was fully equipped (expansion interface, printer, FDD's, modem, etc.) by holiday time of '79. Apparat also sold a replacement OS for the TRS-80, which came out then. That will verify the times at which the Ap ple FDD as well as the TRS-80 FDD became available. It's certainly possible I'm off by a year. However, the TRS-80 was, at whatever time they both had their FDD's available, the only seriously competing system that Apple had to deal with because there weren't any other single-supplier systems available, yet. At that point there was no VIDEX board yet, either, IIRC. A year later things were completely different because of the VIDEX board, the SVA FD interface, VISICALC, and a number of other things. It was not my point, by the way, that Apple built their drive as an answer to Tandy, but, rather, that they did the things they did in order to save money on their floppy drive subsystem, because they were expensive back then. They saved lots of dough with their tightly integrated drive/controller arrangement since they not only used a really cheap set of electronics, and quite a clever one, but didn't have to pay tens of bucks for a then-still-very-costly FDC chip. That was a VERY big cost advantage, which, as I wrote before, didn't show up as a price reduction that you'd notice. As for the error rate, there were numerous assessments published over time, and because their bit-error rate wasn't an entire order of magnitude higher, Apple was able to brush it aside as "not even an order of magnitude" higher. It's been studied extensively and perhaps there are even better figures on it now than there were back then. The fact that it provided effectively double-density media capacity made it a reasonable tradeoff for the not-totally-professional user. I'm not sure about what figures were developed regarding disk-error-induced system crashes.