How to transfer data FAST?

[Jerome H. Fine]

 >Zane H. Healy wrote:

>>So tell me, what are the really cool methods to transfer data between a 
>>PC and a real PDP11 at a reasonable speed? SCSI controller and SCSI 
>>disk? Something else? Ethernet?
>>
>>Or is a backup over serial line a normal thing...?
>>    
>>
>
>It helps that I have SCSI Controllers on my operational PDP-11's.  I use
>removable disk trays that allow me to move the HD's between PDP-11's, and
>more importantly to hook them up to a Unix box, at which point I can use
>'dd' to back them up.  The resulting disk images can be accessed via SIMH,
>E11, or burned to a CD-R and accessed on the real PDP-11 HW.  I've managed
>to boot and install RT-11, RSX-11M, and RSX-11M+ from CD-R.  I've yet to
>figure out how to do that with RSTS/E.  I also typically have either a TZ30
>(half-height SCSI TK50 drive), or a TLZ06 (4mm DAT) drive hooked up.  I
>prefer to use DAT, however, RSTS/E software doesn't really like trying to be
>installed from DAT.
>
>  
>
Jerome Fine replies:

Since the most expensive part of a SCSI connection to a real DEC Qbus 
backplane
with a PDP-11 is the SCSI Qbus host adapter, then if anyone already has 
one, I
recommend a magneto optical (with removable media) disk drive.  While 
300 MBytes
these days is very small, about 5 years ago, I purchased a number of 
Sony SMO
S-501 magneto optical disk drives (when they were already 10 years 
old).  I also
have a good quantity of media - which since they are double-sided (but 
the drives
can read ONLY one side at a time) actually hold 600 MBytes in total.  
And since
the drives are much faster than both a TK50 and a TK70 (aside from also 
being
random access), they are much better than both tapes.  Since I don't 
know how
fast a TLZ06 tape drive performs, I can't comment.

As for a transfer between different systems, I find that the magneto 
optical is
both fast enough and large enough for everything I can imagine using RT-11.
The cost of a Sony SMO S-501 is small compared to a SCSI Qbus host
adapter, so I usually have one on each system that uses the media.  In 
addition,
for RT-11, 300 MBytes (8 RT-11 partitions) is sufficient to provide backup
capability.  This dual use (transfer and backup) more than justifies the 
magneto
optical media on a PDP-11 as far as I am concerned.

>Ethernet using either TCP/IP or DECnet is another option that I use to
>transfer data, but I try to only use that for small amounts of data.  One of
>these days I plan to go wireless with my PDP-11.  I'd also like to see if I
>can't get a SCSI DVD-ROM drive running, but considering the difficulty with
>getting a CD-ROM drive to work, I have some doubts on getting that to work.
>
One thing about a CDROM drive as opposed to a DVD drive
on a PC is that the normal (IDE) CDROM drive was not
able to read the first 64 blocks (16 CD sectors) of the
CD under E11 using RT-11.  My DVD drive on the PC does
allow E11 under Windows 98 SE to read those first 64 blocks
of the CD and I can BOOT  RT-11 on the PC under E11.

As a result, I do not have much of an incentive to acquire
a CDROM drive that will work with my SCSI Qbus host adapter
on the PDP-11.  If ever anyone is discarding such a CDROM
drive, please let me know.  It would be "nice" to be able
to boot from a CDROM drive on a real DEC PDP-11 system.

Sincerely yours,

Jerome Fine
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