HP 16700A CDROM option for reignite

[DIPLover]

I just got a 16700A mainframe today, with 2x 16557D cards.

It passes all self-tests and appears to work fine. No visible corrosion on the bottom of the cards near the plastic stiffeners yet so I am busy removing the hardened foam residue. I have done 1 board so far, didn't break anything and it still passes tests.

The machine is running version 1.50 of the LA software, and that will not be sufficient for an incoming trio of 16752B cards.

I have gotten the software ISO for version 2.90 from archive.org but now I need a CDROM to install.
External SCSI CDROMs on ebay are crazy expensive at the moment.
Is there a way to connect an internal SCSI drive temporarily and boot from that just for the reinstall?
and if so, do I need a 50 pin or a 68 pin internal drive?

Edit :
I see 2 50 pin connectors on the PCI board, can they both be used? Is that what they did in the 16702B?
Anybody actually reinstalled that way before?

[MarkL]

...
Edit :
I see 2 50 pin connectors on the PCI board, can they both be used? Is that what they did in the 16702B?
Anybody actually reinstalled that way before?

The 16702B uses the same SCSI bus for the hard drive and the CDROM.  The CDROM is a Plextor PlexWriter 40/12/40S (PX-W4012TS).  It is a 50-pin bus and the hard drive is address 6 and the CDROM is address 1.

Sorry I can't help on the 16700A specific questions; I haven't used one.

You could buy a couple of 16702B for what people are asking for the SCSI CDROM.  There's an empty 16702B on ebay right now for USD$99+shipping and with option 003 = expanded memory.  Item #332626511962 if you're interested in an upgrade that has the built-in CDROM.  (Not my listing/no affiliation).

[Stray Electron]

  Some of the old HP, SUN, and SGI systems don't issue the bytes per sector command to the drive and some do so.  One the ones that don't issue the commands, you have to set the jumpers on the drive to default to the correct number of bytes per sector in order for the device to boot from the CD drive.

[DIPLover]

I have option 003 on my 16700A as well as 4620B software option. It has the modern fan configuration and is in pretty good shape.

Shipping to Canada is usually the killer and I don't want the built-in screen so I'll pass on the 16702B.

Thanks for the heads up and for confirming the 02B uses both internal connectors. Since they use the same software and the hardware is so similar I'm pretty confident it will work.

I will give it a try using the second internal SCSI connector and a plextor drive I have.

[gslick]

Edit :
I see 2 50 pin connectors on the PCI board, can they both be used? Is that what they did in the 16702B?
Anybody actually reinstalled that way before?

I believe the way it works is that with the two 50-pin SCSI connectors on the 16700A 16700-66504 and 16700B 16700-66510 PCI boards one of the connectors goes to the SCSI host controller and the host connector goes to the rear panel HD50 SCSI connector. Then the internal cable that plugs into both connectors on the PCI board and to any internal SCSI devices places those devices on middle of the SCSI bus. If there are no external devices attached then active termination on the PCI board next to the HD50 connector terminates the bus. If there are any external devices attached then the active termination on the PCI board is disabled and the external devices on the end of the SCSI bus must be terminated.

If your thought was to unplug one end of the internal 50-pin cable leaving the other end plugged into the other connector on the PCI board, and temporarily plug an additional 50-pin cable into the now empty connector on the PCI board to connect the second cable to a SCSI CD-ROM drive, I don't think that would work, you would end up with one of the two devices on an isolated bus.

What you could probably do is find another internal 50-pin cable that is long enough and has enough connectors on it that both ends could plug into the PCI board and also connect to the hard drive and the CD-ROM drive. Or only plug one end into the PCI board and terminate the other end. On the PCI board there are visible traces from the 50-pin connector J10 to the active termination chips next to the external HD50 connector, so I assume the 50-pin connector J1 must be the one that is connected to the SCSI host controller.

[MarkL]

I can confirm that J1 is the one to use.  I've done exactly what gslick is describing in running two drives from J1 with the termination enabled on the last drive.

There's only one SCSI controller in the system (on J1) and J10 is indeed just a path to the back panel connector.  J10 can provide auto-termination if you don't have a terminator or selectable termination on the last drive.

Caveat this is on a 16702B, but it sounds like the 16700A is the same as far as the SCSI config is concerned.


If your Plextor doesn't work, there's also this gadget which can emulate a hard drive or CDROM:

  http://www.codesrc.com/mediawiki/index.php/SCSI2SD

I've used the v5 hardware in hard drive mode and it works.  The v6 hardware didn't work for me when I tried it a year or so ago, but they claim the 16700A is (now?) supported.

[MarkL]

I have option 003 on my 16700A as well as 4620B software option. It has the modern fan configuration and is in pretty good shape.
...

Just a side note that the B4620B license and many others are available for free for non-commercial use (so you're not necessarily tied to your 16700A for that reason).  See here for additional license key info:

  https://www.eevblog.com/forum/testgear/hp-16702a-drive-replacement/msg770247/#msg770247