USING TAPES ON ACS

INTRODUCTION

In the past, big, multi-user systems typically stored large datasets on tapes housed in the computing center. On ACS, you can maintain your own tapes, using our I/O (Input/Output) station or the I/O Window Facility. You can read files in from tape and store your datasets on ACS disk in your home directory (for small datasets) or in special files systems (for very large datasets). You can also write files back out to tape, but only at the I/O Station.

Information Technology provides two different facilities for tape handling:

Help Desk I/O Station

An I/O station maintained at the Help Desk at 111 Cummington St. supports the following tape media:

150 Mb QIC 1/4" tape cartridge
5.0 Gb EXABYTE 8mm data tape cartridge

There are many utilities available to transfer files between the I/O station tape drives and ACS. Among the most commonly used are: tar, cpio, and dd. A Help Desk consultant can help you use the I/O Station.

I/O Window Facility

The I/O Window, also located at 111 Cummington St., maintains a facility which you can use to have data from tapes created on other systems loaded to ACS. The tapes can be in the format of IBM standard labelled or non-labelled tapes.

nine track tapes at 1600 and 6250 bpi (read only)
3480 tape cartridges (read only)

A facility exists on ACS to transfer files from tapes to either the user's home directory, for small files, or to special file systems, for large files. This facility consists of two parts; a program to transfer the contents of a tape to a temporary disk storage area, and programs to scan and extract tape files from the 'diskized' image:

The tload program submits a request to operations to temporarily load the contents of a tape to ACS. Data can be loaded to ACS from nine track tapes at 1600 and 6250 bpi and from 3480 cartridges.
Once the data has been transferred to ACS two programs -- scantape and readtape -- are available for you to review and extract files which you can save for future reference.

As noted above, this facility is 'read only', i.e., once files have been transferred to ACS from reel-to-reel tape or 3480 cartridge, they cannot be written back out to reel-to-reel tape or 3480 cartridge. You must use the Help Desk I/O Station to write files back out to tape or diskette.

LOADING FILES

Run the tload program to notify operations of a tape load request.
Check in the tape at the I/O Window in the basement of 111 Cummington Street.
Within a few days, Operations will load the tape into a 'disk image' which can be processed like a mounted tape. You will be notified by e-mail when this data is available, reminding you that this virtual mount will be there for 7 days, and that the tape must be checked out of the I/O window within that time.

EXTRACTING FILES

After you have been notified that the tape has been loaded, it will be 'virtually' mounted 24 hours a day for 7 days. You can access the data files on the tape directly from this virtual mount using the readtape and scantape programs on ACS. They provide an easy way to copy whatever files you wish from the disk image to your permanent storage (e.g., home directory, /ue/N file system, or, via ACS-IO to 8mm tapes).

Once the tape files are extracted via readtape, they can be kept on ACS disk (if space allows) or transferred to another medium (see Transferring Files on ACS for additional file transfer options). See a Help Desk Consultant if you need to maintain your files on ACS and think that your storage requirements will be high.

REFERENCES

I/O Station

See the online man pages for tar, cpio, dd, dosread, ord doswrite. Also see the man pages for mt and tctl -- two utilities which pass subcommands to a tape device.

I/O Window

See the online man pages for tload, scantape, and readtape.