FS: System 36

From: Richard Erlacher <edick_at_idcomm.com>
Date: Sat Jun 2 09:56:43 2001

Don't ask me about this ... contact chaikensys_at_aol.com directly, plz.

Re: FS: IBM System 36.

>Take it away for $100. I love when people say an item for sale was this many
>dollars new, well this is a real bargain cause it was about $100,000 new. What
>a steal!! LOL.
>Midtown NYC location.

----- Original Message -----
From: "Jerome Fine" <jhfine_at_idirect.com>
To: <classiccmp_at_classiccmp.org>
Sent: Saturday, June 02, 2001 8:24 AM
Subject: Re: Interesting find

> >Chuck McManis wrote:
> > In packing up my stuff to move it from the office building to a temporary
> > holding facility in my garage, I discovered I had the other half of the MDB
> > Unibus to QBus bus "interpreter" which the docs claim will allow me to
> > either use Unibus peripherals on a Q-bus machine or vice versa. Way cool.
> > This means I can set up my 11/34a to use the RQ11D talking to a ESDI drive
> > in a BA23 box as its hard drive (plus an RL01) but this gives me much more
> > capacity. I hope it works!
> Jerome Fine replies:
> Since even V5.03 of RT-11 allows for up to 8 * 32 MByte partitions for
> the MSCP/DU(X).SYS device driver (the first version of RT-11 that did
> provide for partitioned MSCP devices, you should really enjoy an ESDI
> hard disk drive. If you do find a drive that is more than 256 MBytes or
> eight partitions, you can still use the extra "devices" as data volumes
> under V5.03, but just not at the same time since the limit in V5.03 is
> eight drives at one time (DU0: => DU7:) out of the 256 possible partitions
> on an 8 GByte hard drive (I guess that would be SCSI - not ESDI).
> Of course, if you have V5.05 of RT-11 or later, that allows up to 64
> partitions at one time after you do a SYSGEN. The PDP-11/83 that
> I have available has 3 * 600 MByte ESDI hard drives. Eventually I
> hope to add a 4th drive for scratch use - the RQD11-EC quad controller
> allows only the first three drives to be WRITE PROTECTED with a
> passive front panel - I use an alligator clip connected to the correct wire
> on the 10-pin connector tied to ground at all times except when I decide
> to write something to be saved on the hard drive - if you are using the
> drive as the system device and you don't like the error messages about
> the SWAP.SYS file, then "SET EXIT NOSWAP".
> One minor problem is that until after V5.04G of RT-11, there was no
> possibility of booting (even a software boot using DUP) since the boot
> code had ONE missing instruction to set up the partition number. I have
> fixed that in my version of DU(X).SYS for V5.04G and could easily
> do so for V5.03 as well. In V5.06 of DU(X).SYS, the ONE instruction
> has been added to the boot block code, but you can still boot only the
> first eight devices via DUP (DU0: => DU7:) since there are only eight
> entries in the boot block for the required map. I have also fixed that in
> my version of DU(X).SYS for V5.06 of RT-11 and can now boot
> D00: => D77: via DUP. The reason I found this aspect important is
> that with the 3 * ESDI 600 MByte hard drives, is use:
> D00: => D23: for the first 20 partitions on physical unit 0
> D30: => D53: for the next 20 partitions on physical unit 1
> D60: => D83: for the next 20 partitions on physical unit 2 with
> ASSIGN D54: D80:
> ASSIGN D55: D81:
> ASSIGN D56: D82:
> ASSIGN D57: D83:
> and when I add a small ESDI scratch drive as unit 3 which can't
> be WRITE PROTECTED, I will use:
> D90: => D93: for the remaining 4 available partitions on unit 3 with
> ASSIGN D24: D90:
> ASSIGN D25: D91:
> ASSIGN D26: D92:
> ASSIGN D27: D93:
> so that everything is easy to see and understand and all the drive
> numbers have a bit of sense and order.
> If you don't understand any portion of the above, ask some questions.
> I hope the hardware works for you.
> Sincerely yours,
> Jerome Fine
Received on Sat Jun 02 2001 - 09:56:43 BST

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