PDP 11/34

From: Jerome Fine <jhfine_at_idirect.com>
Date: Sun Jul 1 08:55:23 2001

>Zane H. Healy wrote:

> >Will keeping them in an unheated garage cause much damage,
> >or should I make an effort to get the units to the basement.
> Well, my PDP-11/44 is kept in an unheated garage (though it does get heat
> from the house) that can get plenty hot in the summer, and very cold in the
> winter. Prior to my getting it, the /44 sat in Paxton's old Warehouse for
> who knows how many years. I think cleanliness is of more importance than
> wide temperature changes. Because of this I keep the /44 covered with old
> sheets to try and keep most of the dirt out of it.

Jerome Fine replies:

Plenty hot in Ottawa in the summer can still be over 90 degrees Fahrenheit
in the summer with VERY high humidity. But in winter, minus 40 degrees
is not uncommon - humidity is probably not important (and Fahrenheit
is not required since the same value applies to Centigrade as well).

By the way, if you are running RT-11, one RK05 for the system files
(about 5000 blocks) is usually enough and another RK05 drive can
hold the data files - another 5000 blocks. I ran that way for many
years in the early 1980s. Just keep each project (if you actually have
any) on a separate data RK05 disc pack.

An RL01 is much nicer for RT-11 at 10,000 blocks and the RL02
(uses the same Unibus controller) is wonderful at 20,000 blocks.
I am currently running a simulated RL01 drive under the E11 emulator
and it is only half full. Of course, for data drives I am "cheating" a bit
since I have I have 3 * 32 MBytes RAM disks available while I do
multiple assemblies and 2 * 256 MBytes of Sony SMO S501 magneto
optical disk drives to make permanent copies of the files on the RAM
disks when I decide it is time to test the programs. All the RAM
disks and the Sony drives are under one MSCP DUX.SYS device
driver that can reference up to 64 partitions in RT-11 or 2 Gbytes
of disk space at one time. This is such a change from just 2 RK05
drives that I can hardly remember having just 10,000 blocks in total.

However, the interesting part in RT-11 is that although it may be
a bit inconvenient, it is still possible to write the same programs
and execute mostly all the same software even on an 11/34 with just
128 KBytes (even if just half populated with memory) although
perhaps just one program at a time. Yes, and one additional
factor - SLOOOOOOOOOOOOOOOOOOOOOOW.

Did you receive any system software and if so do you know which
version of the operating systems are available?

Sincerely yours,

Jerome Fine
Received on Sun Jul 01 2001 - 08:55:23 BST