I lament that he didn't spend a chapter or two on a floppy disk and floppy disk controller. I would like to see a detail treatise on that, I've never seen one.
Maybe its straightforward, drag and drop from the FDC data sheet into a bit of code. Then again, maybe not.
Even when he did the SB-180, his 64180 based SBC, it has an FDC, but he does not talk of it much.
He also did some articles on an 8088 computer. This was interesting because it came out in that seeming millisecond of time between CP/M and MS-DOS, but before "PC Compatible". His computer could run MS-DOS (or, I reckon, CP/M-86), but it was not a PC Compatible.
But it was just a couple of articles, not a book like this was.
Mind, he spent much of his time in the controller world, not really the desktop world. The SB-180 was a bit of a anomaly in that sense, as it was more of a full desktop machine than most of his other work.
FDCs were tricky things. When reading you had to pick up a byte every 8 usec, when writing you had to be ready with the next byte in the same amount of time, and a whole sector's worth would need to be dealt with without interruption. (Idk if the number was exactly 8 usec, but it was in that neighborhood)
Most of the early 8 bit micros couldn't service an IRQ fast enough to keep up, so you'd be more likely to see a polling loop, but even those had to cut things tight. I saw some 1.7MHz 6809 code that could just about do it. Not sure how the old TRS80s dealt, maybe LDI type things? I know the IBM 5150 relied on a DMA chip to shift the sectors to/from disk. Would be fun to find out what the old S-100 systems did.
Maybe its straightforward, drag and drop from the FDC data sheet into a bit of code. Then again, maybe not.
Even when he did the SB-180, his 64180 based SBC, it has an FDC, but he does not talk of it much.
He also did some articles on an 8088 computer. This was interesting because it came out in that seeming millisecond of time between CP/M and MS-DOS, but before "PC Compatible". His computer could run MS-DOS (or, I reckon, CP/M-86), but it was not a PC Compatible.
But it was just a couple of articles, not a book like this was.
Mind, he spent much of his time in the controller world, not really the desktop world. The SB-180 was a bit of a anomaly in that sense, as it was more of a full desktop machine than most of his other work.