StorageTek tape formats
From Wikipedia, the free encyclopedia
Storage Technology Corporation (StorageTek) has created several magnetic tape data storage formats. These products are commonly used with large computer systems, typically in conjunction with a robotic tape library. The most recent format is the T10000. StorageTek has primarily competed with IBM in this market.
Contents |
[edit] Cartridge formats
Most (but not all) modern tape cartridges are made in the 3480 format, which was popularised by IBM. This is a small, rectangular and easily handled tape cartridge compared to the previously common 7-track and 9-track round tape reels. It proved rather suitable for use in automated tape libraries.
The tape is internally wound onto a single hub, mounted entirely within the external shell, and presents one end for the tape drive to engage and thread into the tape drive for reading or writing. The mechanical design of this loading mechanism varies between different types of tape media and is a common source of failures. Usually the tape cartridge incorporates a switch that can be set to permit or forbid writing of data to the tape.
It is very common for the tape cartridge to be identified by an external label or sticker, which is normally both in human readable characters such as AB1023 and also in bar code, to be read by devices in an automated library.
At the end of the tape, the drive reversed the direction of tape motion, moved the read and write heads slightly vertically across the tape, and continued to write (or read) more data until the beginning of the tape was reached. This process could be repeated many times, laying down several track sets on the tape media in a serpentine recording mode. The Storage Tek 9840, 9940 and T10000 drives are all serpentine recording drives.
The Storage Tek SD3 drive was different, being based upon a modified video recording device. The tape advanced steadily, and data was recorded (or read) by a cylindrical head rotating at high speed and inclined at a small angle to the direction of tape motion, laying down (or reading back) a series of short data tracks very closely spaced together.
The Storage Tek 9840 series of drives used a relatively unusual dual tape hub mechanism within the 3480 format shell, similar to the familiar audio tape format. This reduced the length of tape that could be stored inside the shell, and hence reduced the data capacity of the cartridge. However, it made the loading or threading of the tape into the drive very fast, which was useful in business applications.
| Format | Date | Capacity (GB) | Data Rate (MB/s) | Load time (s) | Reel Configuration | Announcement |
|---|---|---|---|---|---|---|
| 4480 | 0.04 | 3 | 8 | |||
| 4490 | 0.80 | 4.5 | 8 | |||
| 9490 | 0.40-0.80 | 18-20 | 4.3 | |||
| SD-3 | 1995 | 10-50 | 11-18 | 17 | ||
| T9840A "Eagle" | 1998 | 20 | 10 | 12 | dual reel | |
| T9840B | 2001 | 20 | 19 | 12 | dual reel | |
| T9840C | 2003 | 40 | 30 | 12 | dual reel | |
| T9940A | 2000 | 60 | 10 | 59 | single reel | |
| T9940B | 2002 | 200 | 30 | 59 | single reel | |
| T10000 | 2006 | 500 | 120 | 62 | single reel | [1] |
These tape formats are typically used in a mainframe environment. Drives used ESCON, FICON, Fibre Channel, or SCSI interfaces.
[edit] SD-3 (Redwood)
This format used helical scan on a 1/2 inch tape. Three different capacities of tape cartridge were offered: 10, 25 and 50 GB, differing only in the length of tape wound on the reels and in the external media identification character, A, B or C, which was designed to be read by the Powderhorn automated library's bar-code reader system.
The drive was based on a professional Panasonic video recording system, modified to be suitable for digital data recording. The result was a large, heavy drive of considerable complexity. Although somewhat difficult to maintain, it won popularity among some users due to the relatively low cost of the media per Gigabyte.
[edit] T10000
The T10000 is StorageTek's latest tape drive and cartridge for mainframe systems. It holds 500 GB (native) and can transfer data at 120 MB/s (native).
[edit] External links
|
|||||||||||||||||||||||||
