Subject: DEC pdp8F!

From: [email-masked] (Crisis Computer Corp)
Date: Thu, 1 Sep 1994 00:21:18 GMT

Can anybody tell me the difference between a pdp8e from a pdp8f?

Basic board set are the same but "e" and "f" has to have a reason.

I'd appreciate a reply either through this newsgroup or e-mail me at

[email-masked]

Neph Medina
800/726-0726
408/270-1100 USA
408/270-1183 FAX

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From: [email-masked] (Douglas W. Jones,201H MLH,3193350740,3193382879)
Date: 1 Sep 1994 13:59:33 GMT

>From article <[email-masked]>,

> Basic board set are the same but "e" and "f" has to have a reason.

The power supply difference:  An 8/E uses linear regulators, while
an 8/F uses a switcher.  The difference is measured in pounds and
watts, and is significant!

The front panel difference:  An 8/E uses incandescent lamps, while
an 8/F uses LEDs.  Late 8/E systems used 8/F front panels.

Box size:  The 8/E had room for 2 backplane modules of 20 slots each,
knock off one one for the front panel and 2 for the jumper, and that
means you could put 37 boards in the machine.  The 8/E power supply
was big enough for that load.  The 8/F had room for only 1 backplane
module, so you could put 19 boards in it.  The power supply was
downsized accordingly.

In performance, they were identical.  If you added external expansion
boxes, they could be expanded to similarly huge configurations.  If
you wanted a minimal system, however (and most PDP-8 systems ever sold
were pretty minimal), the 8/F came in at a lower cost.

Now, a far harder question?  What was the difference between the 8/F
and the 8/M?  One correct answer:  The difference in silkscreen
lettering on the front panel insert.

Actually, the 8/M was an OEM machine, and most were sold with only a
blank minimal function panel on the front.  The 8/F was sold to end
users who didn't need the expansion capability of the 8/E, so most were
sold with full function front panels.  All the same options applied to
the 8/F and 8/M, however.

It's all in the FAQ, next posting scheduled Oct 8, but you can look
at the most recent version in the archives on:

	ftp://rtfm.mit.edu/pub/usenet/alt.sys.pdp8
	ftp://ftp.uu.net/usenet/news.answers/dec-faq
	ftp://src.doc.ic.ac.uk:/pub/usenet/news.answers/alt.sys.pdp8
	ftp://sunsite.unc.edu/pub/academic/computer-science/history/pdp-8/docs

Automatic translations of the FAQ to HTML format (as used by World Wide
Web) are available from:

	http://www.cis.ohio-state.edu/hypertext/faq/usenet/dec-faq/top.html

				Doug Jones
				[email-masked]