Old Disc Drives - SCSI Hard Disk Drives

Synopsis

SCSI stands for small computer system interface. For a longtime it was the go-to interface for high-speed magnetical storage. And as of 2021 it might still be. I had my first SCSI host adapter somewhere back in 1996 or so.

Seagate ST-52160N

One Sunday morning, while wandering through the tons of crap at the local flea market, I have spot this oddball Seagate disk bearing the Medalist logo. A shrink down 3.5" half-height format with a SCSI cord attached. I knew I had to pick this up.

Back at home, I learned that this belonged to a line of music synthesizers. In fact, it was entirely loaded with samples and synthesizer specific files.

One thing I have noticed is that this small disk makes an annoying pitch spindle motor noise. I don't think the bearings are off course. I heard other disk drives emitting the same noise when they were new. But this drive is slow! In my tests, with the Adaptec AHA-1542CF ISA bus SCSI host adapter, it performed bad. I was not expecting this. But I guess a synthesizer does not need a fast drive. However, the construction is beautiful. It speaks the quality language. It even has 128K cache memory on-board and on the fly ECC correction.

But if I think better, maybe the old Adaptec board was the bottleneck. It has to be this. I don't have a PCI SCSI host adapter to test SCSI devices. I'd better not discredit this little drive too much as I could be talking sh*t.

In the end, I sold it to someone needing a disk drive for his Korg keyboard. I kept the 50-pin SCSI cord. Never know when this might come in handy.

TECHNICAL DATA

CAPACITY: 2.17 Gb
ACTUATOR TYPE: VOICE COIL
DISCS: 2
MEDIA TYPE: THIN FILM
RECORDING METHOD: PRML 0,4,4
SPINDLE SPEED: 5.397 rpm
INTERFACE: SCSI (50-pin)
AVERAGE ACCESS: 11 ms

Quantum ProDrive LP-52s

The 50Mb Quantum ProDrive model LP-52s hard disk drive was factory fitted in my Unisys 286 / 10 MHz machine. It was connected to an Adaptec AHA-164x 16-bit ISA bus SCSI controller, capable of delivering a mind-blowing 5 Mb/s. The drive made the 286 machine appear really fast. Even if we are talking about a 286, the machine was faster in comparison to the same machine equipped with a Western Digital WD1004-27X drive controller and the Seagate ST-238R disk drive.

This drive has an unspecific size and that is why it is easy to remember. Quantum really paid attention to the optical aspect of this drive. The entire disk drive is extremely light. The aluminum case is probably what makes it so light. As you can see from the picture, Quantum put a sticker on the top cover that says POWER REQ: 5/12V and 6W. This is an important aspect that not many companies decided to specify on the drive's top cover.

I did not wanted to open the lid of this drive to take a picture of the inside because it still works and has not even a single bad sector on it. The drive, making good pair with an Adaptec AHA-154CF SCSI controller, was originally used to create, store and serve this Internet site. For an entire year or so, this site was served from that disk.

As for the other aspects, I would like to mention that this drive gets a little hot while running. In fact it runs hotter than any similar drive of it's capacity and age. The mechanical design of this drive is also very good. In it's silver aluminum case, the drive looks great and Quantum did it again releasing this good drive back in the year of 1990. I can't accurately date this drive because there is no date sticker attached. The only way I can date it is to turn it upside down and to read on the DisCache® chip the year 1988. Also on the PCB is etched 1990 so I supposed this particular model appeared in 1990.

The layout of the components on the PCB is quite good and you just can't miss the shape of the LED if you ever get your hands on such piece of hardware. All my respects to Quantum for this great drive.

Later Edit: This drive died by a very common cause: stopper rubber started to melt and the head assembly sticked to it preventing the initialization sequence. I decided to disassemble the drive and took some pictures before I finally recycled it. Here they are. I still find these drives beautifully constructed.

Magnetic read/write heads.

Interesting optical construction. I guess this thing determines the position of the heads on the platter. There was a complicated photo-emitter and its receiver and this glass thing was freely moving between them.

Head amplifier integrated circuit.

Head assembly.

I bent one arm for picturing purposes.

The magnetic platter is beautifully marked with an interesting font.

Magnetic platter details.

Magnetic read/write head details.

That's it. This drive is terminated.

TECHNICAL DATA

CAPACITY: 50.1 Mb
ACTUATOR TYPE: VOICE COIL
DISCS: 2
MEDIA TYPE: THIN FILM
RECORDING METHOD: RLL 1,7
SPINDLE SPEED: 3.662 rpm
INTERFACE: SCSI (50-pin)
AVERAGE ACCESS: 17 ms

Thank you for spending your time reading these old pages.