Hello,

* Martin Oehler (martin.oehler AT gmx DOT net) [20030124 11:52] thus spake:
> Hi, Jon!
> 
> Am Fre, 2003-01-24 um 16.27 schrieb Jon LaBadie:
> > 
> > Maybe you hit what Gene describes in another posting today.
> > Once a tape has been written to with HW compression, the drive senses it
> > and automatically switches to HW compression regardless of settings.
> 
> No, I made a mistake (see my reply to Genes posting).
>  
> > What capacity were you expecting for "native", uncompressed data?
> 
> I expect 100 GB. The drive specifications can be found at:
> http://www.storage.ibm.com/hardsoft/tape/3580/prod_data/g225-6854.html
> We use the internal version of the drive.
> 
> > According to docs/TAPETYPE:
> > 
> >     The speed is currently unused.
> > 
> > Is this an HP drive by any chance?  ISTR they have some auto-slowdown
> > system to match scsi-bus speed.
> 
> # cat /proc/scsi/scsi
> Attached devices:
> Host: scsi1 Channel: 00 Id: 04 Lun: 00
>   Vendor: HP       Model: Ultrium 1-SCSI   Rev: N23D
>   Type:   Sequential-Access                ANSI SCSI revision: 03
> 
> If the measured size and filemark is correct, do you have an idea
> how I will be able to use the drive with 15MB/sec?

That all depends on your scsi or FC controller and pci bus.

I have 4 Seagate LTOs in a STK_L40 library connected to differential
scsi controler -- one for each drive. diff scsi because of cabling
issues: LVD is a little less sturdy than differential scsi but that's
besides the point. I have an O3800 so I can shove 60MBs doen its
throat no problem. In your case you have to ask yourself: is my pci
bus wide and fast enough to sustain 15MBs? 

Here's my tapetype for my Seagate Ultrium:

define tapetype Ultrium-SGT-LTO {
    comment "just produced by tapetype program"
    length 101376 mbytes
    filemark 0 kbytes
    speed 15084 kps
    lbl-templ
}

HTH,
jf

> 
> Regards,
> Martin Öhler
> 
> 

-- 
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