RX33 (or RX50) image of XXDP?

Jerome H. Fine jhfinedp3k at compsys.to
Sun Apr 8 21:43:42 CDT 2007


 >Ethan Dicks wrote:

> >On 4/6/07, Jerome H. Fine <jhfinedp3k at compsys.to> wrote:
>
>> If you are able to burn a CD-R, INCLUDING  BLOCKS 0-63 (which
>> are sectors 0-15 on a CD), you can also boot from a SCSI CD
>> drive with unit 0 under E11 and using your PDP-11.  I don't
>> think that SIMH allows a CD to be used as a raw device
>
> That sounds like a Windows limitation.  Under UNIX, you just give simh
> the raw drive name, like /dev/hdc for an IDE CD-ROM drive that is
> primary on the second IDE chain.  There is no equivalent under
> Windows.

Jerome Fine replies:

I am not surprised.  For a while, I was going to use
raw RZ28D-E which are just ST32550N (3.5" 1/2 HT 2 GB)
under E11 which can hold just about 64 RT-11 partitions.
BUT, I could never easily bring them on line when I
first booted W98SE.  Instead, I powered up a Sony S-501
without the optical platter inserted.  Since the platter
is removable, W98SE was told to NOT complain.  However,
I then turned the power off on the Sony S-501 drive and
turned the power on for the ST32550N drive.  Miracles
were performed and E11 was then able to see and:
MOUNT  DU0:  SCSIn:  (n was the SCSI ID for the drive)

I concluded that since the ST32550N drive did not have
a file structure (such as FAT32) recognized by W98SE,
the W98SE, in its great wisdom, refused to bring the
drive on-line.  Problem seems to be that under Windows,
format includes a file structure which must be one that
is recognized by Windows.  No possibility of a "FOREIGN"
file structure is ever considered as a valid possibility
by Microsoft.

But it was almost trivial to work around the problem
as explained above.  Fortunately, Sony S-501 drives
were also inexpensive as well as useful for making
backups.  The optical platters hold 295 MBytes per side
while was sufficient even 5 years ago to be cost effective
in holding 4 RT-11 partitions.  Of course, now with SATA 2
drives with over 500 GB, there is so much room and these
SATA 2 drives are so fast that the opticals are no longer
very useful.  And with 8 GB DVD-R media (I will eventually
buy one although the 4 GB are still quite large enough),
I still only need 3 DVD-R to hold a monthly backup of all
my files.  All of my RT-11 files fit on a single DVD-R.

It really is amazing.  I think it was around 1995 when I
bought an XT8760E (600 MByte ESDI) for about $ 600 as an
end of line sale item.  Within a few years, I was able to
buy Hitachi ESDI drives of the same size for about 10% and
I used 3 such drives on the PDP-11/83 for many years with
2 drives for on-line backup and with TK70 for off-line backup.

DO  NOT  READ  BEYOND  THIS  POINT  -  OFF  TOPIC!!
Well, I guess a lot of the previous stuff as well!!

By 2002, I started using W98SE with 3 * 40 GB drives with
2 drives for on-line backup and DVD for off-line backup.  My
son wants me to switch to a Pentium 4 (after all, PCs only last
about 3 years) using Windows XP and 3 * 320 GB drives.  It looks
like I will actually be able to keep all 37,607,912,018 prime
numbers up to 10^12 in 18 files of 2 GB each (I only need
a single byte to store the differences) using only 10% of the
storage available.  And I will still be able to run RT-11 under
E11, but 100 times as fast as a PDP-11/93.

Sincerely yours,

Jerome Fine
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