I have to defer to your more recent experience. Aside from the occasional job requiring my portable development station, I seldom used CP/M after 1984 or so. I did have a farily flexible prom programmer with which I could program parts not yet supported on my PC-based programmer, but in the span between '81 and '84, I had other concerns. I have no idea, however, how you block and deblock I/O with 1K blocks when you have only 1k in your sector buffer. I suppose I could go back and look at the software, but the stuff I had at my disposal at the time seemed to work best with a big hard disk requiring the largest available granules (allocation blocks) and since the logical drives were limited to 8MB and since CP/M was pretty much a thing of the past, I didn't see any point in wasting time and resources fine-tuning it. I used it because I had a few already-paid for cross assemblers and other tools for CP/M. Once a decent version of the PC-DOS became available, I was sure to make the switch. Of course I didn't realize how long that would be. Nonetheless, once I had a PC with a '186 processor, I could run the CPM emulator to use my tools and the more modern hardware to do my work, and the CPM became a relic. It had performed fairly well and competitively with the PC up to the point at which I got an XT clone which used a '186 at 16 MHz. Together with a couple of fairly fast drives it outperformed CP/M on the Z-80 even when it was emulating CP/M. Dick -----Original Message----- From: Allison J Parent &lt;allisonp(a)world.std.com&gt; To: Discussion re-collecting of classic computers &lt;classiccmp(a)u.washington.edu&gt; Date: Monday, March 29, 1999 8:01 PM Subject: Re: followup: Rinky dink hamfest <snip>