XKL TOAD (was: Re: How to tell differential scsi drives and cards apart)

Rich Alderson RichA at vulcan.com
Wed Jan 14 13:20:48 CST 2009

> From: Patrick Finnegan
> Sent: Tuesday, January 13, 2009 9:36 PM

> So, for curiosity's sake, how much money did a Toad-1 sell for when they
> were being produced?

A base system cost $125,000 in 1995.  That comprises

    1 XKL-1 CPU (PDP-10 architecture, all KL-10 user code compatible,
      although the I/O instruction set differs radically)

    1 XRH-1 4-port FASTWIDE differential SCSI controller (allowing
      attachment of up to 15 devices/port)

    1 XNI-1 4-port Ethernet interface, providing AUI and 10baseT

    1 XMG-1 32MW memory (KL-10 physical maximum is 4MW)

    1 4GB disk drive (internal to system cabinet)

    1 DDS-2 tape drive (HP OEM, with a Paralan single-ended to
      differential card)

That took up 4 slots of the 7 slot backplane.  At XKL, we installed a
full 128MW in a system just to verify that our OS mods to support it
worked correctly, and it passed all tests with flying colors.

We would also sell you an M4 9914 9-track tape drive so that you could
deal with legacy tapes (backups, installation media, etc.) if you wanted.

Later, when we started using multiple 9GB drives in our own systems, we
replaced the DAT drives with Quantum DLT8000 drives.  If we had continued
to sell systems that would have been the configuration you got for the
base price.

A note on the memory:  TOPS-20, as it turns out, is memory-starved on a
KL-10 with the maximum memory.  When MCI/Tymnet replaced two KL-10
systems running an early fork of Tops-10 with a Toad-1 running TOPS-20,
they went from 100 users per system with 1-2 *minute* response times to
200 users on a single system with *subsecond* response times.

Rich Alderson
Server Engineer, PDPplanet Project
Vulcan, Inc.
505 5th Avenue S, Suite 900
Seattle, WA 98104

mailto:RichA at vulcan.com
(206) 342-2239
(206) 465-2916 cell

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