On Tue, Sep 4, 2018 at 10:00 AM, Al Kossow via cctalk <cctalk@classiccmp.org> wrote: > We have two in the CHM collection. This is the first time I've ever seen one > work. I was thinking it might be fun to try to get FORTH running on it.
That sounds cool. > I may also mod mine so that it puts out proper RS-232 levels with a > piggyback board on the 1988. They just power it with +5v, which doesn't > work at all talking to my Mac. An old Wyse-75 wasn't so fussy. Hmm... I hadn't noticed that. Glad you pointed it out. I've had problems in the past with other machines and low-voltages on RS-232. > If you look at the schematic, they did some pretty weird things, like > using a 2758 for address decoding, and then there's the floppy disk > interface.. No error checking? I found that surprising - floppies are hardly reliable enough to forego error checking. > 1980 seems really late to be trying to build a system like this. Agreed. > It looks like a design OSI would have come up with. That was my thought when I saw the 6852. It was either because of OSI or they saw an app note somewhere and decided not to use a WD 177x chip. -ethan
