RE: Capacity of a 3590E cartridge

["Andy Nolen-Parkhouse" <aparkhouse@xxxxxxxxxxxx>]

Oliver,

The #2749 SCSI controller has a rated sustained throughput of 38 MB/Sec.
The drive data rate of the 3590-E is rated at 14 MB/Sec.  Both
capacities are uncompressed rates, so with compression/compaction
active, the actual throughput and drive rating is higher.

There should be no significant relationship between the capacity of the
tape and the throughput of a save.  The documentation indicates that the
3590-E will only reach maximum throughput with a fiber-channel
connection.  On some systems, the drive will never reach maximum
throughput because the computer cannot present data to the drive fast
enough because of processor speed, disk arms, etc.

You can get some impressive compression on certain kinds of saves.  The
3/1 ratio is an average, but if you were to save some libraries which
contain a lot of source code and data files, you could get more.  If
your source code and data files have a lot of blank spaces, the
compression could approach what you're describing.  On the other hand,
if you were saving a lot of compiled objects, you could get less.  What
are you saving when you see 100 GB on a tape?

I've pasted below some documentation from IBM's product description.
The cartridge part numbers may allow you to more accurately identify
your blue tapes.

I hope this is helpful,
Regards,
Andy Nolen-Parkhouse

<From IBM's product documentation>
The 3590 E Model Tape Drives shipped on or after March 3, 2000, or with
feature #5781 (Extended Media Support - EXX), will support two 3590
cartridge types:

The 3590 High Performance Cartridge Tape, which provides up to 20 GB
uncompressed
The 3590 Extended High Performance Cartridge Tape, which provides up to
40 GB uncompressed

The 3590 E Models can read or write twice as much data as the B Models
on the 3590 High Performance Cartridge Tape and on the 3590 Extended
High Performance Cartridge Tape. With the E Models, the cartridge can
contain up to 40 GB of uncompressed data per cartridge.

IBM 3590 Extended High Performance Cartridge Tape (media-type label K):
05H3188  Data cartridge with no VOLSER Label (similar to feature #8140)
08L6087  Data cartridge with Black & White (B&W) Label Only
08L6088  Data cartridge with Color Label Only
08L6089  Initialized data cartridge with B&W Label
08L6090  Initialized data cartridge with Color Label

IBM 3590 High Performance Cartridge Tape (media-type label J):
05H4434  Data cartridge with no VOLSER Label (similar to feature #8130)
05H8220  Data cartridge with Black & White (B&W) Label Only
05H8221  Data cartridge with Color Label Only
05H8222  Initialized data cartridge with B&W Label
05H8223  Initialized data cartridge with Color Label
<End IBM's product documentation>

> Hello,
>
> we have an 3590E tape station and I'm wondering about the capacity of
the
> cartridges. Is it possible that the blue cartridge
> (for 3590B) takes about 100GB of data (compression/compaction
activated)?
>
> If I read the the data sheet correctly, the blue cartridge should fit
20GB
> on a 3590E (w/o compress). Thats an impressive
> compression factor (100GB on a 20GB cartridge).
>
> When do I get the full data rate (27Mb/sec)? Only with the green
tapes?
> Our
> IOP card is a 2749.
>
> Regards,
>
> Oliver