Thinking way ahead of time (changes)
Super Tuesday: Windows stalling migrations

Finding SCSI disks from third parties

Bos2_cover_sm Disk drives are the most likely parts of an HP 3000 to fail, being just about the only moving part in the system. (Tape is the other.) Disks from HP are certified, but they're still more costly than any other kind of storage peripheral. When you walk through Fry's and see a 200 GB disk for $150, you might wonder if there's a chance to use that kind of device in your HP 3000.

By many experts' testimony, there's a good chance that an under-$100 drive will boot up your HP 3000 just fine. These older 3000s use pretty small disks, so the costs of replacement are small, if you go outside HP's inventory. HP's not even making the SCSI-2 drives, the ones shipped with 9x8s, for new sales anymore. Some third party outlets like Phoenix/3000 can get you a remanufactured model of HP drives, but their focus leans more toward HP's VA arrays than an 18GB drive.

If a little drive is all you need, how can you be sure you're buying something that works with the 3000? A few years back John Burke wrote an article for the NewsWire explaining how to do it. HP replied with its set of sensible reasons why the HP-firmwared devices are worth the extra cost. But a few more years and lot less Low Voltage Device inventory is making more customers look at replacing their 3000 disks that are 8, 10, even 15 years old.

3000 storage experts like Denys Beauchemin have years of evidence that HP's disk standards have not been essential for reliable 3000 service.

I have been using non-HP firmwared disk drives in my HP 3000 for over 10 years now. "SCSI is SCSI," and as long as you can get your hands on a 50 pin SE or LVD disk drive, or if you can get a converter from 68 PIN to 50 pin you should be good to go.

Or if you would rather have something with a newer manufacture date than 1997 (that's so last millennium,) pick up any current (or at least 21st century) LVD-SCSI drive and get a 68-pin to 50 pin converter and have at it.

The converter can be had at, where Granite Digital Part 6980, 80 SCA to 50m IDC (no termination) runs about $40. While Beauchemin said that with such an 68-50 connector "any LVD drive will work on an HP 3000 9x7 or 9x8," he added that these older peripheral requirements might be one of the best reasons to move away from HP 3000 hardware.

For the last several years I have been harping about people needing to get off the HP 3000 mostly because of the peripherals. There has not been an HVD-SCSI device manufactured this century; SE-SCSI is positively ancient. I also said that even LVD was becoming passé and that new interfaces would supplant all these. SATA was what I had in mind at the time; USB is also very strong, and fiber is de rigueur for real servers.

In a few more years, people will be rummaging at yard sales for SCSI devices. Even now, adapters are hard to find, I remember having some difficulty finding some a few years back. This situation will NOT get better for the 3000 homesteaders.

I notice that Dirtcheapdrives are selling 750GB SATA drives for $500. This is totally unbelievable; 750 gigabytes, in one drive, for 500 bucks. The terabyte drives will be here this year — and people will be looking for 4GB SE-SCSI drives for their 3000s.

Research on SCSI requirements is best started at SCSI FAQ. Adaptec's Web site has good information, too. Allegro's Stan Sieler recently posted a comprehensive list of Seagate's disk ackronyms for their drive interfaces. "Seagate drives indicate their interface via the one or two letters at the end of the model number."

LC  Low Voltage Differential, 80-pin SCA
LCV Same as LC, but with an increased cache size
LW  Low Voltage Differential, 68-pin Wide SCSI Connector
LWV Same as LW, but with an increased cache size
N   SCSI, 50-pin Narrow SCSI Connector
DC  Differential, 80-pin Single Connector Attachment (SCA)
ND  Differential, 50-pin Narrow SCSI Connector 

Then, the high-voltage differentials, (HVDs) which can't be used with a simple adapter:
W   SCSI, 68-pin Wide SCSI Connector
WC  SCSI, 80-pin SCA (Hot Swapable)
WD  Differential, 68-pin Wide SCSI Connector

So as an example, a Seagate ST318404LC (Cheetah 18GB 10,000 RPM) has a low-voltage (LV) 80-pin interface. Coupled with the converter, it can work with a Series 918 to replace original drives, if you use the original drive cable in the 3000.

Beauchemin offered us a good handle on history of these interfaces:

SE-SCSI is very old (20+ years) and was almost the original SCSI. It stands for Single-Ended SCSI. Speed is 5 MB/second and the cable can’t be very long, 6 feet or less.

Then came UltraSCSI or HVD-SCSI. The speed was up to 20 MB/second (or even 40, but I’m not sure.) The good thing with HVD is that you could go long distances, 25+ meters with it. It uses the difference in voltages between pins, whereas SE SCSI uses absolute voltages that are very low to begin with. If you remember RS-232 and RS-422, it’s the same principle here. RS-232 was based on signals having a (low) voltage and no voltage and RS-422 was based on the differences in voltage between signal pairs. Which is why RS-232 was certified for 50 feet and RS-422 could go thousands of feet.  It’s all a question of resistance and signal attenuation.

However, it seems that HVD had a speed limit associated with it, perhaps that speed of light thing. Also, as devices became (much) smaller, the need for long distances went down or was better addressed with fiber optics which is insensitive to stray electrical signals.

So, SE came back in vogue, but this time as LVD or Low Voltage Differential. When you plug a single-ended device in an LVD string, all devices, including the host bus adapter, drop down to SE signaling and to the speed of SE-SCSI. So, as long as you can account for the 50 pin to 68 pin thing, either with a cable or an adapter, LVD and SE devices can co-exist, at SE speeds.

In the last few years the replacement for LVD-SCSI has been SATA or Serial ATA.  Which may be what the guy at DCD was talking about. LVD SCSI was in vogue until very recently for servers; I don’t think it has completely disappeared.

LVD hasn't disappeared. HP has a Web page that refers customers to adapters from Rancho SysTech, to bridge this gap from the 900 Series 3000s that use HVD drives to the more-available LVD drives.