> From: Johnny Billquist
> the ENABLE board that I used on an 11/34 did not add neither split I/D
> space, nor supervisor mode. Essentially it made the 11/34 look like an
> 11/24.
Right, it doesn't add any modes, or separation, or anything like that; just
more memory. It's entirely separate from the CPU; it just sits in the middle
of the UNIBUS.
Noel
John Foust <jfoust at threedee.com> writes:
> I'm trying to understand at a low level how some early computers
> and game consoles generated a non-standard form of NTSC.
There's a pretty good description here, with diagrams of the video
waveforms involved for both PAL and NTSC (both use the same idea):
http://martin.hinner.info/vga/pal.html
In brief: a video signal consists of a series of fields (about 60 per
second for NTSC). Each video field starts with a series of "vertical
sync" pulses that returns the electron beam to the top of the screen
(there's also a "horizontal sync" pulse at the end of each line, which
moves the beam back to the left of the screen). There are different
vertical sync pulse sequences for odd and even fields, so the monitor
knows to offset the even field by half a line. A normal video signal
alternates between odd and even fields; in the kind of non-interlaced
signal you're talking about, every frame starts with the odd field
vertical sync, so the monitor always pulls the electron beam back to the
same place.
Cheers,
--
Adam Sampson <ats at offog.org> <http://offog.org/>
> From: Pete Turnbull
> 2.9BSD doesn't need split I&D, but 2.11BSD does.
Doesn't 2.11 also need Supervisor mode (at least, for the networking code)?
Of course, there is not (AFAICR) any machine with split I&D but not
Supervisor, so the question above is purely intellectual, not of practical
consequence. (Unless you have an 11/xx with an Able ENABLE board! :-)
Noel
I'm trying to understand at a low level how some early computers
and game consoles generated a non-standard form of NTSC.
The Wikipedia http://en.wikipedia.org/wiki/Low-definition_television says:
"Older video game consoles and home computers generated a nonstandard NTSC
or PAL signal which sent a single field type which prevented fields from
interlacing. This is equivalent to 240p and 288p respectively, and was
used due to requiring less resources and producing a progressive
and stable signal."
Another source says this was true for the "NTSC Atari 2600, Apple II
family, Commodore 64, Nintendo Entertainment System, Sega Master
System, and the vast majority of games for NTSC Genesis, Super NES,
PlayStation, and Nintendo 64."
This page http://www.hdretrovision.com/240p/ calls it a "special timing
signal" and gives examples of how contemporary flat-panel TVs can
misinterpret the old signal. The issue has spawned the creation of
dozen of devices to give the retro look on new TVs.
- John
Hello,
checking on bitsavers for bare presence is not a problem at all...
I should assume that all the documents widely available on other sites
(like manx or related links)
are also on bitsavers?
I mean, searching on bitsavers and not founding a specific file there is
enough to assume that the file is unavailable
and should be scanned?
Anyway, I would need some advice about the way to transfer scanned files
(huge unprocessed/uncompressed or
post-processed to bitmap with level/contrast adaption) to the archive.
Andrea
So, I need to add a PROM burner to my collection of stuff, and I'd like to ask
for recommendations.
I'm looking for something that's easy to find on eBay, not _too_ expensive,
and can handle (via the appropriate adapters, which should also be relatively
easy to find) a very wide range of old PROMs/EPROMs from back in the day.
(I.e. ability to support modern chips is not really an issue.)
The ability to read them would be a real plus (no idea if that's a common
capability or not). Serial interface preferred, but I could work with parallel
(again, no idea what was usual).
Thanks in advance for any insight!
Noel
3 lowboy racks:
Rack1: Vax 11/750
Rack2: Cipher (looks like a F880), and some hard drives appear to be present
Rack3: DecTalk and a VME 68030 system "stuffed with boards"
Intonation is "Free to a good home". Location is just north of Boston, MA
Contact me off-list if interested.
Best,
J
[Seen thanks to off-list assistance - thank you!]
> Brief background: Real VAXes had real diagnostics. MicroVAXes had diagnostic$
I'm fairly sure the MDM is not what I have, then.
> Moving on: Are you aware of
> EK-O19AE-SG-005_MicroVAX_Troubleshooting_and_Diagnostics_May89.pdf
I wasn't. I picked up a copy and it turns out to be unreadable for me;
the ghostscript I have says "Unable to process JBIG2Decode data. Page
will be missing data.". Modern Ghostscript is no longer suitable for
open-source use, so I'm looking for alternatives, either other
PostScript renderers or something to replace the JBIG2Decode code in
the version I have. I have a few leads, but even in the best of
outcomes it will take time.
> Does your emulator have a console ROM like the real thing? Does it have any $
Yes. It is an image of the ROM from a real KA630 I have. In
particular, it has the same set of tests the real thing has. The
simulator passes all of them, as far as I can tell.
I have a copy of EK-KA630-UG-001 and have scanned it, and read it
multiple times. As far as I can tell the tests there are all run at
startup, and they all pass. If there's any way to run any other tests
>from the ROM, I don't know what it is.
I'll also see if I can find that MDM thing, though if you couldn't find
a copy it seems unlikely I will.
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