zaphod@madnix.UUCP (Ron Bean) (12/21/90)
In Article <1990Dec12.065224.10906@i88.isc.com>, botton@i88.isc.com (Brian D. Botton) writes: >......my machine started having memory problems in low memory, i.e., the area >of memory that the diagnostic disk doesn't check because it that's where it >get loaded. The technical reference manual talks about a memory diagnostic >ROM as well as a monitor ROM. If anyone out there has either one of these, >please let me know, I'd like to make a copy of them. My first reaction is that you should be able to test that memory without changing the ROM. Since you know how the boot loader works, why not write a floppy-based diagnostic program that starts by relocating itself into some other area of memory? > I am looking for suggestions for addition to the ROM. As it sits now, the >ROM uses only ~4k out of a possible 32k. What would you like to see? Is it >worth the trouble to put a monitor program in so you can hack at the lowest >level? How about being able to tell the system to boot from a different >disk then drive 0? I'm wide open for suggestions, and possibly some help. I'd like the ability to boot the regular diagnostics disk (or equivalent) from a terminal on the serial port. Someday the CRT will go up in smoke and there may or may not be spares available by then. Unix itself shouldn't care, but can the diagnostics be redirected? I should memorize the keystrokes to park the disk heads (I've never understood why it couldn't park the heads just before it prints "Press RETURN to reboot"). Someone mentioned the possibility of using a multisync monitor (are they available in monochrome?). Does anyone know anything about the CRT controller? Maybe it can be reprogrammed for a cheapo monitor? Lots of time to work this out before the supply dries up, but let's not wait until it's too late... ================== zaphod@madnix.UUCP (Ron Bean) {harvard|rutgers|ucbvax}!uwvax!astroatc!nicmad!madnix!zaphod
thad@cup.portal.com (Thad P Floryan) (12/22/90)
zaphod@madnix.UUCP (Ron Bean) in <1659@madnix.UUCP> writes:
[re: 3B1 monitors]
Someone mentioned the possibility of using a multisync monitor (are
they available in monochrome?). Does anyone know anything about the
CRT controller? Maybe it can be reprogrammed for a cheapo monitor?
Lots of time to work this out before the supply dries up, but let's
not wait until it's too late...
Hundreds of stores, catalogs, discount houses, etc. advertise $50-$70 monitors
for use with "Hercules" graphics (720x348) for "IBM-PC"-like systems, with a
choice of paper-white, amber, green, and other phosphors. Should be NO
problem at all hooking up one of those to the 3B1's video signals; I've been
thinking of doing this myself for two reasons:
1) I intensely dislike the (present) green phosphor ... the color reminds
me of something I heard of 30+ years ago when I was a kid: "Goat Vomit
Green" (contrasted with "Pygmy P*ss Yellow" or "Baby Sh*t Brown" :-),
2) I'd prefer a 13-15" screen, and (yeah, I can't count :-)
3) I'd like to hook the video signal into one of those LCD-screens for
use with an overhead projector for room-viewing of the 3B1 screen's
display.
I may just try this during the upcoming holidays. Looking at the video signal
timing, there's NOTHING special about the 3B1's video. Some eleventy-seven
million "IBM-PC"-type systems also use Hercules graphics monitors. Just put
a DB-9 connector on the case and plug a video cable into the monitor.
Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]