Some more info on the Philips P3800, and P4500

From: Jules Richardson <julesrichardsonuk_at_yahoo.co.uk>
Date: Sat Nov 2 04:22:01 2002

Will,

> I came across a site today which provided more information on this critter,
> and as Fritz had suggested, it is indeed a TurboDOS machine.. I have a copy
> of TurboDOS around, but I don't know if Philips used a custom version or ?

no idea on the data front. Did TurboDOS have built in multi-user support (I
know nothing about it)? If not then I'd definitely think that the version on
this machine was custom, as it has support for at least 4 if not 5 terminals in
its current state.

That's just going by the cables at the back; there's a lot of unused pins on
the card edge connectors, so given that the website claims support for 62
terminals I expect it could make use of some breakout box arrangment to give
more 25-pin terminal connectors.

> Not to mention that I don't have a clue how I'd copy it, or even what
> TurboDOS runs on. Here's the link I found to the info on the P3800:
> http://www.digidome.nl/philips1.htm

unfortunately I hit a bit of a snag with my machine. Following the flood damage
the previous owner had tried to fix the system. Trouble was, the machine has
two backplanes to it - the upper one with one row of card sockets and the lower
one with two rows. System cards from the top rack will also plug into the
bottom rack (which contains the PSU, mains voltage, and a spare slot for some
unknown board). The disk controller had been plugged into that spare slot...
:-(

It wouldn't have got any mains voltages but it would have got +5 and +12V on
all sorts of pins that it shouldn't have. I also found that the disk data bus
(SCSI? SASI?) terminators had been misaligned and so it's possible some of the
data lines were shorted together or at least had a low resistance connected
across them.

Curiously, the disk controller and the board the converts the system's
SCSI/SASI bus to MFM look to be identical on the P3500 (from the photos on the
website that Fritz posted about). So if one of those ever shows up, at the very
least it'd be invaluable for checking that the hard drive on this 3800 is still
operational - and in the absence of schematics for the 3800 it'd probably be
very useful for fixing the 3800's disk controller.

> Also, the P4500 is a minicomputer of some kind, apparently..

I'm not sure - I did a quick hunt on the web and there was very little
information around. One site seemed to imply that it was much older technology
than the 3800, but another site gave the impression it was much newer. Uless
the model number was reused they can't both be right :)

cheers

Jules


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Received on Sat Nov 02 2002 - 04:22:01 GMT

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