Ardent Tool of Capitalism

IBM Hard Drives

Note: These hard drives are mostly 50 or 68 pin SCSI. Features and Specification PDFs are not available for all drives, so I grabbed the Product Summary instead.

Note: I do know most early ThinkPads used either IDE or DBA-ESDI. Early non-MCA PS/2s used MCA-IDE. Later PS/2s used MFM, ESDI (or even ST506) or SCSI.

The 9533, 9553, Reply upgrades, 9556 / 9557, and 9576 / 9577 systems at a minimum, could potentially use one version of IDE or another.

If you are looking for 80-pin (SCA), SSA or FC-AL specs (RS/6000), they most likely are available, but since I do not use them (YET) they are not here.

j_mcspec.pdf DASD Storage Interface Specification Micro Channel (REV 2.2)
(retrieved from Internet Archive)

Travelstar (2.5” mobile computers)

Deskstar (3.5” desktop computers)

Ultrastar (3.5” servers)

Other IBM disk drives

Peter Wendt's comments about the different IBM hard drive types (unconfirmed):

It is better to buy appropriate drives for the purpose: 50-pin types like the DORS for the desktops with onboard SCSI or "Tribble" / "Spock" / "Spock Prime", DCAS, DCHS in 68-pin for the Fast / Wide arrangement in Server 85 and 95 Non-Array and DFHS, DCHS, DDRS in 68-pin version for the Server 95 Array / Server 3xx, 5xx "Hot Swap" bays. These drives were designed to fully support the Hot Swap function - which is not the case on the "workstation drives" DCAS and DORS.

0662? (Spitfire) and DFHS are not recommended if you plan to sit next to the machine. There running loud, hot and are power hogs. Same with DFRS to avoid like the plague

DFHS

Use them externally in an enclosure with sufficient room and additional fans with enough airflow in length over the drives.  IBM made pretty bad first series DFHS. They were hot, loud and had problems with the internal controller microcode as well as with the surface coating which leads to "sudden death".

There were "active cooled" 5.25" bays - which have two of these noisy "trouser button" fans ... which (in theory) should keep the drives cool enough. Practice shows, that these thingies are only nerving loud and fail occasionally (like CPU fans - they are similarly lousy). DFHS are -like the Quantum Atlas II and III- intended for servers which supply active cooling. Parts of the DFHS heat up to 95C.

The older DFHS series 1 (the "Fat Ones") get really hot - and are not recommended. Towards the end of the series the drives get better.

DFRS

Keep away from DFRS - they are "refurbished" (hence -R-) DFHS that had been sent back for repair and returned to the spares cycle. These "refreshed" drives have a large black stripe on the barcode label with white "RE" in it atop. They are second choice.I had three of them - all are dead in the meantime."

> My tip, try to get DCAS, DDRS or even DNES drives and try to get a fast/wide (corvette) controller.

DDRS

7.200 rpm version of the DCAS. They're 7.200rpm - but don't make much noise. The DDRS finally was the 3rd generation drive (after DFHS and DCHS) where they learned to handle the problems. I have 7 of them in my Server 520 (DDRS-34560 UW, some LVD) along with 2 x DCHS and 2 x Quantum Atlas. The DDRS is available as 50, 68 and 80 pin version. For the Server 95A "non Array" with F/W "Corvette" I would pick the 68-pin version and tailorize an appropriate SCSI 68-pin cable. The DDRS superseded the DCHS, which superseded the DFHS.

DNES

The follow-up to the DDRS was the DNES, which is a good 7.200rpm drive and viable at ebay in masses. Short-lived because 10.000 rpm DRVS came out. The DNES ran parallel with he DRVS for some time.

DCAS

Not a bad drive - but a 5.400 rpm type. The DCAS was designed for desktops / workstations rather than servers. But they were suitable for smaller servers as well - especially when they were "power-wise and thermally challenged" (mean: small power supply and bad internal ventilation). The DCAS runs pretty cool - only topped by its successor DORS. The DCAS is a nice, fast and low-noise drive.

DORS

5.400 rpm rated 5V/300mA and 12V/200mA, which makes a total of a lousy 4Watts .....It is my favorite desktop drive in old PS/2s (56 / 57, 76 / 77) *because of* its low power consumption.

DPES

"Pegasus" drive is a 5.400 rpm drive designed for desktops. It has about 50% lower current draw and -therefore- runs significantly cooler than the DCHS. With the introduction of the DSAS and DPES series IBM returned to other conceptions of the R/W-amplifiers and different screening of the drive. These are rock-solid general purpose drives, which need no special treatment."

... I've had the "pleasure" of dealing with literally thousands of IBM SCSI hard drives over the past several years.  In the 9.1GB size, the DDRS, DNES and DPSS all did well -- very few bad drives, they all have good reliability.  The DCHS family I would avoid -- we had about a 5% fallout rate after several months of use.

The DDYS family was better than DCHS, but not as good as DDRS/DNES/DPSS.  For a sample size of only one or two, it's hard to say, because you might have the good luck to get one of the "better" drives in the lot, or you might have the bad luck to get one of the few "bad" drives.

DDYS

Ed. Not a bad drive, but check on the fab. The DDYS fabs were in Japan, two in Thailand, one in Singapore, and one in Hungary.

IBM WILL OFFICIALLY officially close a hard drive plant in Hungary by the end of November, "due to weak global demand", it was revealed today. Source

Our sources, however, reveal that the real reason for the Hungary pullout is because of extremely poor quality, and major product control and quality control failures.

Peter wrote:
   some outstanding poor-quality DDYS 36GB's ... that failed after a few weeks when been hard ridden in RAIDs. My own record was 24 drives in 2 days for one customer... Argh! The lot of them were made on Saturdays and Sundays according to the date-of-mfg stamp. Judge yourself. IBM claimed it were caused by a change of the magnetic coating - but I could prove that it was in fact largely day-of-the-week dependent. At least for 9 out of 10 dead drives. Imagine the funny faces they made when being confronted with my list.)