Category Archives: Retrocomputing

Better error recovery in floppy disk formatter

I put some better error recovery code in floppy disk formatter for the verify pass.   Previously I was getting verify failures on drive 0 when using double density, and the new code reveals that some of them are cleared up … Continue reading

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Quay 900 internal photos

Mark Wickens asked for photos.  I haven’t taken many, but here are two.

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Quay floppy formatter

I did a lot of cleanup of my floppy routines, and got the formatter working with double density.  Right now it only runs as a “standalone” program.  Once I have CP/M running on the Quay, I’ll put in conditionals to … Continue reading

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BYTE conolidated adveriser index for vol 1 & 2 available

I’ve added volume 2 to the BYTE consolidated advertiser index.  It is provided as an ODF (Open Document Format) spreadsheet.

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BYTE consolidated advertiser index, Quay ads, 8080 XPL0

I’ve been compiling a consolidated advertiser index for the early years of BYTE magazine, thus far from V1N1 (September 1975) through V2N3 (March 1977).  Hey, that’s one more thing to add to my Retrochallenge project! This did turn up some … Continue reading

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Quay 900 stuff

I have a Quay 900, which is an obscure Z80-based system from 1979.  It has two MPI (CDC) eight-inch double-sided floppy drives, and uses a Quay MPS-90F single-board computer rather than the then-common S-100 bus, though it has two daughterboards … Continue reading

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TRS-DOS as possible prior art for MS patent on exFAT, and reference request

Microsoft introduced a new “exFAT” file system a few years ago, and I wouldn’t care about it in the least, except that it is now the official filesystem for SD-XC cards.  I only care about that in that digital cameras … Continue reading

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TRS-80 Model II TRSDOS: paranoia strikes deep

It looks like the developers of TRS-80 Model II TRSDOS were very paranoid that someone might be able to bypass the filesystem and access data on a floppy directly.  I’m not sure if their primary concern was file password protection, … Continue reading

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ksim 8080 simulator released

As part of my RC2012WW project, I ran an 8080 exerciser and other instruction test programs on a Sol20 to better understand the behavior of the 8080′s flags (which are NOT exactly the same as those of the Z-80), and … Continue reading

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Simulation success!

By writing some additional 8080 test programs, running them on both the Sol-20 and my simulator, and comparing the output, I’ve found and fixed several bugs in my simulator.  Now the 8080 Exerciser running on the simulator matches all the … Continue reading

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