IBM Hard Drive Assembly (HDA) unit for the 3380 series, first announced in June 1980.

The University of Auckland – Department of Computer Science: Removable 1GB Hard Drive Assembly (HDA) from the IBM 3380 storage device series, announced in June 1980. Another image is available at Wikimedia Common. See also the video embedded below.

The photo shows a single hard drive assembly (HDA) used on the IBM 3380 Direct Access Storage Device (DASD), a series which IBM announced on June 19801. The 3380 series was a storage solution to be use alongside a computer (it was not a computer in itself). Each unit of the early models of the 3380 series (A4, A4F, AA4, AAF, B4 and BF4) was composed of two of those hard drives (or two HDAs). Each of them had a capacity of about 1.26GB, providing one storage device of the 3380 series with a total capacity 2.52GB.

Those were the very first hard drives to break the 1 gigabyte barrier, as explained on the website of the Department of Computer Science at The University of Auckland:

From the early 1960s most disks had platters 14 inches in diameter. This became a standard size for the high-end disks for over twenty years. The high point for the 14 in. disk came with the IBM 3380 (1981) with 9 platters and the breaking of the 1GByte barrier with a capacity of 1260 Mbytes. This device was also housed in the tallest largest cabinet ever used for a disk – truly the pinnacle of large disk development. The IBM 3380 continued in different versions until 1987 with the 3389K drive of 3781 MB capacity. (“Computing History Displays: Fifth Floor – Magnetic Data Storage – Magnetic Disk Storage”)

In an oral history of the IBM 3380 series recorded in 2006, engineers who have worked on it in the 80s reminded the “refrigerator size” of this first gigabyte storage device:

Mike Warner: About $120,000. And for these, and they stood in a meter wide, a meter deep, and two meter high assembly.

Jack Grogan: Called the refrigerator size.

Warner: Yeah, about a big refrigerator, a big, deep refrigerator. So it was extremely difficult to make this large a device, with all its mechanical complications reach the aerial densities and the technical objectives that we had. And we’ll go through that in the next hour or so. (Computer History Museum: “Oral History Panel on IBM 3380 Disk Drive”, interviewed by Jim Porter, recorded on January 3, 2006, Mountain View, California, ref. number X3413.2006, p. 4, PDF)

The weight of a single HDA such as the one depicted in the photo above was about 29 kilograms (roughly 64 pounds)2. The price for one of those 1.26GB HDA was about $50,000. The “Oral History Panel on IBM 3380 Disk Drive” hosted by the Computer History Museum website really is the most detailed documentation available online about the IBM’s 3380 series. IBM Archives also offers some detailed documentation about its 3380 series: “IBM 3380 direct access storage device” (PDF for archive purpose).

However, one of the best way to have a good look at this first gigabyte hard drive is to watch a 10 mins episode of Tested titled “Inside Adam Savage’s Cave: Geeking Out about Bits and Bytes” (Oct. 11, 2012). In this episode Adam Savage explains the difference between bits and bytes and shows what they looked like when they were made out of vacuum tubes. At about 4’14” he presents a HDA unit from the 3380 series ―which he managed to buy on eBay― and talks about it.

For more related documents, consider the following links:

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1. Although the 3380 was announced in June 1980, due to technical problems the first units of the 3380 series finally shipped on October 1981. See Computer History Museum: “Oral History Panel on IBM 3380 Disk Drive”, interviews by Jim Porter, recorded on January 3, 2006, Mountain View, California, ref. number X3413.2006, p. 2 (PDF). IBM also gives 1980 as the date for the introduction of the 3380 series: “20th century disk storage chronology” and “IBM 3380 DASD with IBM 3880”. ↩︎︎

2.I have got the weight of the 3380 series HDA unit from Newcastle University’s Virtual Museum of Computing Artefacts: see “IBM 3380 Disk Drive”. In the video episode of Tested Adam Savage weights the unit he bought at 75 pounds.↩︎︎


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