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Hard Disk Drive History

     

IBM 350 Disk Storage Unit - 1956The Hard Disk Drive (HDD) industry was born in September 1956, when IBM announced the 350 Disk Storage Unit which was attached to the RAMAC 305 computer. The 350 Disk Storage Unit consisted of the magnetic disk memory unit with its access mechanism, the electronic and pneumatic controls for the access mechanism, and a small air compressor. Assembled with covers, the 350 was 60 inches long, 68 inches high and 29 inches deep (1.5 x 1.7 x 0.7 meters) and weighed 2140 pounds (970 kilos). The first units had a capacity of 5 MB and used 50 x 24" platters which rotated at 1,200 RPM with a seek time of 600 milliseconds.
Time Magazine reported the announcement and that the monthly rental was $3,250. At that time an average car could be purchased for $2,000.
See "The hard drive at 50" special report with photos from CNET News.com.

It is expected that by December 2006, 3.5" desktop HDDs will be available with 1TB capacity, rotating at 7,200 RPM and a seek time of 9 ms. Astonishing!


Vendor & Model
Announce
FCS
Capacity (MB)
RPM
Latency (ms)
Seek Time (ms)
DTR (MB/s)
Computer(s)
IBM 350 DSU
9/1956
1957
5.0
1,200
25.0
600
9.7
RAMAC 305
IBM 1311 RDD
10/1962
1963
2.0
1,500
20.0
250
1401, 1620, 70x0
IBM 2311 RDD
4/1964
1964
7.25
2,400
12.5
75
150
S/360
IBM 2314 RDD
4/1965
1965
29.2
2,400
12.5
75
312
S/360
IBM 3330-I RDD
6/1970
1971
100
3,600
8.3
30
806
S/370
IBM 3330-II RDD
10/1972
1974
200
3,600
8.3
30
806
S/370
IBM 3350 DAS
7/1975
1976
317.5
3,600
8.3
25
1,198
S/370
IBM 3380 DAS
6/1980
10/1981
630
3,600
8.3
16
3,000
303x
IBM 3380-D/E
2/1985
1985
630 / 1,260
3,600
8.3
15 / 17
3,000
308x
IBM 3380-J/K
9/1987
1987
630 / 1,890
3,600
8.3
12 / 16
3,000
308x
IBM 3390-1/2 DAS
11/1989
12/1989
946 / 1,892
4,200
7.1
9.5 / 12.5
4,200
3090
IBM 3390-3
9/1991
12/1991
2,838
4,200
7.1
4,200
3090
IBM 3390-9
5/1993

1993
8,514
4,200
7.1
4,200
3090

DSU - Disk Storage Unit, RDD - Removeable Disk Drive, DAS - Direct Access Storage
See IBM archives for other details.

 

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