From: Richard Erlacher <>
Date: Wed Mar 31 01:11:18 1999

Well, now that I've gotten to where, if I smoked, I'd go have a cigarette
while waiting for a 450MHz processor do to something, I'm almost ready to
wire up a 4.5" x 6" card with a Z80-H and a couple of hard disks of that
generation and fire up CP/M just to see how slow it seems now. I haven't
fiddled with one of these old timers in years.

Years ago, I said that computers wouldn't be fast enough for me until
everything I typed for it to do was done by the time my finger left the
return key. Well, we're there now, and they're still a mite sluggish to me
. . .

-----Original Message-----
From: Allison J Parent <>
To: Discussion re-collecting of classic computers
Date: Tuesday, March 30, 1999 4:47 PM
Subject: Re: followup

><I guess it's fortunate there was only one DMA process going on at the time
><else it might have been real sticky figuring out what had been overwritten
><already.. If you were doing a read in order to do a write, using DMA, you
><might actually get tangled up. Fortunately that showed up while the vendo
><was debugging his code, so I didn't have to deal with that.
>Multiple DMA streams are doable too though hard to apply usefully.
><That's quite so. Fortunately one wasn't required to load data at the
><granule size, but rather at the sector size, so you could get by with a
><of a 1K sector. Of course you had to read it before you could write it, s
><you had to wait for the next revolution of the disk. All this went by so
><fast, and, since I didn't run big databases requiring sorts to and from
><disk, I didn't perceive much delay, as it only takes a few revolutions to
><load up a program. So each drive had six logical drives on it.
>I have. Running a pair of drives and using ramdisk and my own smartdisk
>system. That was the speed order as well, the smartdisk system was fasest
>as it hard its own CPU and DMA channel to processor ram using hidden cycle
>stealing plus caching to 4x physical track size. That and a 6MHz z80 and
>dust flew.
><This all sounds like it could be fun if, for example, you're running it al
><on classic and unmodified hardware. I'm not sure I'd want to try to earn
><living that way, though.
>it's more fun on current hardware like 33mhz Z180s and it's still in use
>in odd pockets here and there. I don't (never did) make a living off it.
Received on Wed Mar 31 1999 - 01:11:18 BST

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