selling a blank floppy disk

Tony wrote about Twiggy (Lisa 1) diskettes: Before I acquired any "real" Twiggy diskettes, I hand-made a few by cutting up the jackets of standard 1.2M high-density floppies (which weren't readily available when the Lisa 1 was current in 1983; they became common sometime after the introduction of the IBM PC-AT in 1984). Recently I realized that I don't know whether the 1.2M media is actually appropriate (although it does seem to work). In order to fit 871K on a double-sided diskette, the Twiggy uses a 62.5 TPI track pitch, rather than the standard 40 tracks at 48 TPI or 80 tracks at 96 TPI. Since a common format for a DSDD (not high-density) floppy gets around 720K, and a DSHD gets 1.2M, the bit density may be closer to that of the DD drive. But it's hard to say, since the Twiggy uses GCR at a variable rotation rate. I need to get the specs on a standard 5.25 inch diskette, such as the radius of the innermost and outermost tracks, in order to work it out. I'm guessing that the reason for 62.5 TPI may have been that they may have been able to do that with the standard heads that were intended for 48 TPI drives. More information on the Twiggy drives is on my web page: http://www.brouhaha.com/~eric/retrocomputing/lisa/twiggy.html I saw a letter to the editor of PC magazine (US edition) sometime within the past year. The writer claimed that the idea that the millenium would end at the end of 2000 was stupid; I don't recall exactly what he said about it, but it was something to the effect that it was OBVIOUS that the millenium ended at the end of 1999, and that 2000 began a new millenium. That's not the interesting part. We hear about bozos like that all the time. He went on to "prove" that he was right. He explained that if you are counting coins, that your 100th penny was part of your first dollar. Obviously he didn't actually think about the relationship very hard. Your 1st penny is part of your first dollar, as is the 2nd, 3rd, 4th, [...], 98th, 99th, and 100th. Your 101st penny is the first penny of your second dollar. [Just as the 101st year was the start of the second century, etc.] I was just about rolling on the floor when I read this "proof" of his point. If it had been UseNet, I would have assumed that it was a troll. A lot of people gripe about the lack of a year zero. I try to explain to people that the year numbers are ordinal numbers, not cardinal numbers, which usually gets blank stares. So I then explain that A.D. years are numbered as the first year after the [whatever you call the divider between B.C. and A.D. dates], the second year after, etc., and that the B.C. years are numbered as the first year before, second year before, etc.: baseline event | | <------|------|------|------|------|------|------|------|------|------|-----> fifth |fourth|third |second|first |first |second|third |fourth|fifth |sixth year | year | year | year | year | year | year | year | year | year | year B.C. | B.C. | B.C. | B.C. | B.C. | A.D. | A.D. | A.D. | A.D. | A.D. | A.D. | After seeing it presented this way (usually wider so I can mark the first and second decade), people that aren't completely brain damaged will usually concede that this makes some sense, even if they won't concede that it is "correct". The rest of the people aren't even worth arguing with. Cheers, Eric