>"Zane H. Healy" wrote:
> > I tested a Viking QDT with RT-11 and a 1 gig HD. Of course, I could only use
> > the first 30 megs. This one is destined for a BSD machine anyhow.
> The Viking QDT and RT-11 can address a lot more of a HD than 30Mb. For
> example V5.3 supports 8 partitions (8 * 30 = 240MB), newer versions support
> more. I can't remember off the top of my head how much as I'm running a
> newer version, but I'm using 100Mb and 200Mb HD's under RT-11.
Jerome Fine replies:
You are confusing the maximum number of RT-11 partitions that can be
easily handled by RT-11 at the same time WITH the maximum number
of partitions that RT-11 can see when the command:
SET DUn: UNIT=0,PART=p
is used.
Prior to V5.03 of RT-11, partitions were NOT supported.
For V5.03 of RT-11 up to V5.04G, "n" is from 0 => 7 for a total of EIGHT,
but p has the range 0 <= p <= 255 for a total of 256 partitions. That means
that an 8 GByte drive can be easily managed even though ONLY 256 MBytes
can easily be seen at one time.
The the command changes to:
SET Dnn: UNIT=0,PART=p
For V5.05 of RT-11 up to V5.07, "nn" is from 00 => 77 (OCTAL in essence
although the actual usage of the device name is RAD50 of all three characters)
for a maximum total of SIXTY-FOUR (note that a SYSGEN is required), but
p still has the range 0 <= p <= 255 for the same total of 256 partitions. That
means that an 8 GByte drive is still easily managed, but now 2 GBytes in 64
RT-11 partitions can easily be seen at one time.
NOTE that "UNIT=0" is only in my examples and that any valid physical unit
is allowed.
Of course if your hard drives are 256 MBytes or less, then any distributed
RT-11 monitor for V5.03 of RT-11 and later can look at the whole drive
at the same time. However, I hear that Tim Shoppa has a 9 GByte drive
that has all 256 RT-11 partitions.
> The QDT is a great board, on my /73 I've got a Plextor 8x CD-ROM, DEC TLZ06,
> and two PC Removable disk trays (for easy swapping of HD's) hooked to one.
> I've successfully run RT-11, RSX-11M, RSX-11M+, and RSTS/E on this setup.
> I was originally using 100MB and 200MB SCSI disks, I now use 2GB 7200RPM
> Seagate Barracuda's.
I also have a number of ST32550N drives as well with 31 RT-11 partitions.
Under Ersatz-11 on a PC with a host adapter, I am able to interchange them
at will with a real DEC PDP-11, although the host adapter I usually use is
a CQD 220/TM. I presume that a real DEC RQZX1 is probably still more
expensive - does anyone know?
> > I got the QDT for $45 on eBay. Someone put it up with a buy-it-now of $45.
> > Someone tipped me off, and I got there first. It pays to keep a sharp eye on
> > eBay. I just bought a KDJ11-SD off eBay for $5. This is a nice one: rev -09
> > CPU, 18 MHz, 1.5 megs RAM. Other recent eBay steals: RQDX3 for $10, DESQA
> > for $8.50.
> Nice, it shows I've not been keeping a close enough eye on eBay.
> Zane
Those prices are unusual, but do occur if you watch for them. Often they are
offered AS IS and you take your chances. When the board still works (which
is usually most of the time as it happens), the buyer has struck gold.
Sincerely yours,
Jerome Fine
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Received on Thu Feb 27 2003 - 18:30:18 GMT