Hi Fabio,
I think, that your proposals can't be successfull. How I understood Iomega's
tech support, the tape drive needs a minimum rate of 2000MB/s. This is the
reason, why it won't run with a standard floppy controller, but only with
special high speed controllers. So it seems to be a limitation of the ditto
max drive, not ftape, that the drive does not run at 1000MB/s.
Any other ideas?
Karsten
----- Original Message -----
From: Fabio Lissandrini <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, December 02, 1999 9:40 AM
Subject: I: Overrun errors
> Andy Corteen and Martin Jacobs answered to my question regarding the
> "overrun error" of ditto max stating that these errors cannot be prevented
> because of various items.
>
> Now, don't you think that a real alternative to junk the ditto max could
be
> to patch the ftape code in order to let it deals also with speeds lower
than
> 2Mb/s? If we were able to drive the to the streamer at 1Mb/s, I think that
> the global speed factor would be enhanced, because of the reduced
> number of retry due to overrun.
> In fact, 1Mbit/s means more than 7.5 Mbytes/minute that is almost three
> times the rate I measured using a theoretical 2Mbit/s setting.
>
> Actually, if I set the parameter ft_fdc_rate_limit to 1000, the drive
won't
> be recognized nor run. Do someone knows how to modify the software in
order
> to let this value to be accepted?
>
> Another way to follow could be to connect the streamer directly to the
> standard floppy interface, thus avoiding the use of the EZ board, but also
> this seems not to be running.
> In any case, there is the need of a patch.
> If the question is of general interest, I hope that someone that known the
> behaviour of ftape software can help me (an someone else, too!)
> Thank you
> Fabio Lissandini
>
> ----- Original Message -----
> From: Fabio Lissandrini <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Monday, November 29, 1999 10:36 AM
> Subject: Overrun errors
>
>
> > After a few trial, I've been able to drive my ditto max with the Sept
11th
> > version (unstable) of ftape.
> > Now, I observe that the speed is very slow. I got, on the average, about
> > 2Mbytes/minute: this means that, for a backup that is expected to fill a
> 5MB
> > tape, it will be necessary more than 41 hours!!! This fact seems
strange.
> > So, I had a look at the system log, and I saw that very often there is
an
> > "overrun error" followed by a retry that writes ok. Each overrun is
> > accompanied by a audible tape rewind of about a few 100ms. It's obvious
> that
> > such a lot of mechanical rewinds increases the total time needed for a
> > backup, so slowing down the entire process.
> >
> > I made a trial on the same pc, booted with dos, running the "ditto
tools"
> > program furnished by Iomega. Doing a backup with this, there is no
audible
> > rewinds, and the backup completes at a speed that is not revolutionary,
> but
> > is almost three times faster than the linux trial.
> >
> > So, it's clear to me that the problem is not hardware. The documentation
> > states that in order to avoid overruns, the parameter ft_fdc_threshold
> > should be put at 15. But this doesn't bring to any improvement.
> >
> > Is there a way to avoid the overruns?
> >
> > P.S. the configuration of the EZ board is quite correct. The same
> io/irq/dma
> > found by isapnp has been used for the ftape initialization; they are not
> > used by another application; the ft_fdc_threshold is 15.
> >
> > Thank you in advance.
> > Fabio Lissandrini
> >
> >
>
>
>
>
>
>
>
