The IBM 3850 Mass Storage System

The following photos were taken by Bob Resnikoff about 1982. The IBM 3850 Mass Storage System was the monster storage device of its day. Columbia's MSS had a capacity of 102.2 GB: 2000 cartridges of 50MB each; it was used to hold the entire 1980 USA Census database and make it available to users of Columbia's IBM mainframe computers.

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This is the front of the MSS, where new cartridges can be inserted or old ones disgorged. This is only one of eight cabinets. Each cabinet is about three feet wide, so the MSS was over 20 feet long (see last photo below).


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Interior of the MSS, looking in from the right side. The honeycombs that contain the data cartridges are left and right of the interior cavity.


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A section of MSS honeycomb, with some chambers empty and others containing data cartridges. Cartridges were cataloged on and staged to a set of four IBM 3330 disks, more or less transparently to the user. Cartridges were fetched from the honeycomb by a mechanical hand at the intersection of travelling X and Y wire cables, brought to a reader/writer that unspooled the magnetic tape. The data transfer was transferred to/from disk, and then the tape was returned to its cartridge, and the cartridge returned to its cell by the roving hand. Two tape cartridges made a 100MB 3330 disk.


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The Data Recording Device (DRD), the mechanism that extracts the tape from the cartridge, reads and/or writes it, and then puts it back.


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A panoramic machine-room view with the MSS in the background. Because of the foreshortening and distortion of the wide-angle lens, the massive size of the MSS can not be fully appreciated in this picture. A modified 3830 controller, Mass Storage Controller (MSC), is internal to the MSS. At left center are two IBM 3830 control units and the four 3350 staging disks (which ran in 3330 mode because the MSS software didn't support 3350s).

CLICK HERE for a color shot of a bit of the honeycomb from IBM's Attic.

Photos (and most of the information): Bob Resnikoff.
Most recent update: Thu Mar 25 13:01:37 2004


Frank da Cruz / fdc@columbia.edu / Columbia University Computing History