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CNS News
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For many years, customers needing a low-cost, high-capacity storage system for their data have used magnetic tape. CNS currently has approximately 25,000 physical tape cartridges which we store for our customers. These cartridges, which represent a two-decades-old technology, are bulky, slow, and require human-operator intervention to physically locate and load cartridges into a tape-drive each time a program wishes to access one.
CNS is currently in the process of installing a new "Mainframe Appliance for Storage" (MAS) system from Bus-Tech, which is a virtual tape server that uses software to emulate standard tape cartridges on modern hard-drive-based systems.
Emulating tape operations using low-cost "open systems" disks accelerates performance, enhances reliability, minimizes data errors and takes up less data center floor space. In addition, this emulation means that the virtual "tapes" appear the same as physical tapes to applications; thus eliminating any need for our customers to modify their applications to take advantage of the new technology.
Beyond simply migrating to modern technology, this change provides several advantages to our users:
Capacity: While the upper-limit of a physical 3480 tape cartridge is approximately 200 megabytes (uncompressed), the virtual tape server can be configured to provide considerably larger capacity. As a result, many current multivolume data sets may be able to be condensed down to single volumes.
Mount-Time: Mount-time is near-zero for a virtual tape. There will no longer be a need for the system to send a message to an operator's console and then wait for the operator to locate the tape on the shelf and load it into a tape drive. The data is available immediately.
Access-Speed: While traditional physical tape systems had to read a tape from the beginning, moving sequentially through the files on the tape, a virtual drive can access data at hard-disk speeds. This has the potential to provide significantly faster "tape I/O" and a significantly shorter run-time for programs using tape.
This change is being implemented in a manner which should minimize (if not eliminate) the need for any JCL changes to existing jobs.
The transition could take up to a year. During that time, at least some of the existing IBM 3480 drives will remain on-site. For the future, there are plans to acquire a 3490-compatible drive which will allow us to read 3480 and 3490 tapes that users bring in to the data center and load the data into the VTS.
Charging. At this time, the details of changes to be made to the Charging Algorithm as a result of this transition are still under discussion. An announcement will be made when and if it is determined that changes are appropriate.
We recommend that all interested users subscribe to
VTS-Announce-L by sending a short e-mail to
LISTSERV@LISTS.UFL.EDU with the command
SUBSCRIBE VTS-ANNOUNCE-L as the body of the message. Users
wishing to participate in e-mail discussions and receive announcements about this change should
subscribe to yourFirstname
yourLastnameVTS-DISCUSS-L. The example below
illustrates (approximately) how your subscription request should
appear.
TO: LISTSERV@LISTS.UFL.EDU
FROM: you@your.email.address
SUBJECT: ignored
subscribe vts-announce-l yourFirstName yourLastName
We welcome your comments and suggestions on this and all CNS documentation. Please send your comments to: