HP 7935
Encyclopedia
The HP 7935 was a business computer hard disc drive system manufactured by Hewlett Packard. It was produced by the Disc Memory Division in Boise, Idaho
USA beginning in 1982 at a cost of about $27,000. The internal code name for the drive was "BFD", an acronym for "big f'in disc", a term relative to the smaller 7920 series drives introduced earlier by the company.
The drive's linear motor was so powerful if the feet were not down, when in operation the drive could literally move about the computer room.
Height: 82.5 cm (32.5 inches), Width: 55.2 cm (21.7 inches), Depth: 83.4 cm (32.8 inches), 154 kg (339.5 lb.)
model 97935 Disc Pack.
The HP7933 was the same basic drive with a disc pack only removeable by service personnel.
The 793x series provided a 300% increase in capacity of the HP 7925 at only a slightly increased cost. Performance-wise, the 7935 had a 15-20% performance decrease compared to the 7925. Apparently modifications were made by HP, in a program called the Performance Enhancement Project, raising 7935 performance 15% making it comparable to the older model.
The HP 7935/33 achieved a track density of 625 tracks per inch (considered high at the time), achieving capacity using 7 platters, 13 data surfaces and 14 heads (one head and surface were used for servo data). The disc pack spun at 2694 revolutions a minute.
Despite an extensive air purging spin-up sequence to prevent disc and head contamination, human users reportedly caused so many 7935 packs to have disc head crashes, many users simply purchased the 7933.
interface mounted in the rear. The drive's front panel had a key pad for running internal disc drive diagnostics, a LED
character display, a load and unload button, and a lid opening button.
The 7935G was a bundled package of three 7935H units at a reduced cost of $74,000.
series family of minicomputers and later in early versions of the HP 9000
series computers. Drives were connected via the HP-IB interface to the host computer and multiple drives could be connected in a daisy-chain. The HP-IB address of the drive was selectable via DIP switches next to the interface.
The robustness of the drive hardware was tested by the 7.1 1989 Loma Prieta earthquake. The HP campus in Cupertino had 1,682 HP 7935 drives operating at the time of the quake and 97.25 percent were still operational afterwards. Within an hour, only 2 percent were non-operational and only 1.5 percent were non-operational serveral days later.
Later with development and production of smaller, rack mountable, high-density, sealed HP disc drive units using winchester mechanism designs (like the HP 7963), the demand for HP793x drive line declined.
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....
USA beginning in 1982 at a cost of about $27,000. The internal code name for the drive was "BFD", an acronym for "big f'in disc", a term relative to the smaller 7920 series drives introduced earlier by the company.
Size
The 7935 had four bottom mounted casters for moving and four lock-down feet for stability in the computer room.The drive's linear motor was so powerful if the feet were not down, when in operation the drive could literally move about the computer room.
Height: 82.5 cm (32.5 inches), Width: 55.2 cm (21.7 inches), Depth: 83.4 cm (32.8 inches), 154 kg (339.5 lb.)
Media
The HP7935 allowed the user to remove and install a 404 megabyteMegabyte
The megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000...
model 97935 Disc Pack.
The HP7933 was the same basic drive with a disc pack only removeable by service personnel.
The 793x series provided a 300% increase in capacity of the HP 7925 at only a slightly increased cost. Performance-wise, the 7935 had a 15-20% performance decrease compared to the 7925. Apparently modifications were made by HP, in a program called the Performance Enhancement Project, raising 7935 performance 15% making it comparable to the older model.
The HP 7935/33 achieved a track density of 625 tracks per inch (considered high at the time), achieving capacity using 7 platters, 13 data surfaces and 14 heads (one head and surface were used for servo data). The disc pack spun at 2694 revolutions a minute.
Despite an extensive air purging spin-up sequence to prevent disc and head contamination, human users reportedly caused so many 7935 packs to have disc head crashes, many users simply purchased the 7933.
Features
The 7935H had a HP-IBIEEE-488
IEEE-488 is a short-range digital communications bus specification. It was created for use with automated test equipment in the late 1960s, and is still in use for that purpose. IEEE-488 was created as HP-IB , and is commonly called GPIB...
interface mounted in the rear. The drive's front panel had a key pad for running internal disc drive diagnostics, a LED
LEd
LEd is a TeX/LaTeX editing software working under Microsoft Windows. It is a freeware product....
character display, a load and unload button, and a lid opening button.
The 7935G was a bundled package of three 7935H units at a reduced cost of $74,000.
Use
The 7933 and 7935 drives were often used with the HP 3000HP 3000
The HP 3000 series is a family of minicomputers released by Hewlett-Packard in 1973. It was designed to be the first minicomputer delivered with a full featured operating system with time-sharing. The first models were withdrawn from the market until speed improvements could be made. It ultimately...
series family of minicomputers and later in early versions of the HP 9000
HP 9000
HP 9000 is the name for a line of workstation and server computer systems produced by the Hewlett-Packard Company . The native operating system for almost all HP 9000 systems is HP-UX, a derivative of Unix. The HP 9000 brand was introduced in 1984 to encompass several existing technical...
series computers. Drives were connected via the HP-IB interface to the host computer and multiple drives could be connected in a daisy-chain. The HP-IB address of the drive was selectable via DIP switches next to the interface.
The robustness of the drive hardware was tested by the 7.1 1989 Loma Prieta earthquake. The HP campus in Cupertino had 1,682 HP 7935 drives operating at the time of the quake and 97.25 percent were still operational afterwards. Within an hour, only 2 percent were non-operational and only 1.5 percent were non-operational serveral days later.
Later with development and production of smaller, rack mountable, high-density, sealed HP disc drive units using winchester mechanism designs (like the HP 7963), the demand for HP793x drive line declined.