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MFM hard disk drives

Pictures of MFM drives found in DEC equipment.

st506c.jpg

The ST-506 was the very first 5.25i MFM hard disk drive, holding a staggering 5 MB. It lent its name to the standard MFM hard disk interface. The ST-506 was made by Shugart Technologies, wich later changed its name to Seagate Technologies.

st506f.jpg

This one lives in a DEC Rainbow and therefore also has the Digital RD50 label on it. It has 153 cylinders, 4 heads, 17 sectors per track.

506bot.jpg

No high integration ic's in those days!

st412.jpg

The ST-412, RD51, 10MB drive. 306 cylinders, 4 heads, 17spt.

st419.jpg

The ST-419 15mb drive. 6 heads, 306 cylinders, 17spt. (This is not a drive usually found in DEC machines, unless put in by the customer themselves.)

rd53-1.jpg

The RD53, or the Micropolis 1325, or 1335. 65MB. 8h 1024c 17spt.

rd53-2.jpg

One gets to fear this label. The RD53 gets finicky when old. Replace it if you can.

rd53-4.jpg

The RD53 jumpers.

mx1.jpg

The RD54, Maxtor 2190. 1224c 15h. Very reliable.

st225-2.jpg

The ST-225, RD31. 615c, 4h. Reliable.

st251-2.jpg

The ST-251, RD32. 6h, 820c. Finicky.

Soon a picture of the Quantum D540, RD52, 30mb drive. 512c, 8h.