Jon LaBadie wrote:
> On Mon, Aug 13, 2007 at 12:48:06PM +0100, Rory Beaton wrote:
>   
>> Quoting Jon LaBadie <jon AT jgcomp DOT com>:
>>
>>     
>>> On Sat, Aug 11, 2007 at 02:28:10PM +0100, Rory Beaton wrote:
>>>       
>>>> grunt:/usr/sbin # amtapetype  -o -e 80g -f /dev/nst0
>>>> Writing 512 Mbyte   compresseable data:  94 sec
>>>> Writing 512 Mbyte uncompresseable data:  82 sec
>>>> Estimated time to write 2 * 81920 Mbyte: 26240 sec = 7 h 17 min
>>>> wrote 2490330 32Kb blocks in 95 files in 12562 seconds (short write)
>>>> wrote 2477223 32Kb blocks in 189 files in 12784 seconds (short write)
>>>> define tapetype unknown-tapetype {
>>>>     comment "just produced by tapetype prog (hardware compression off)"
>>>>     length 78236 mbytes
>>>>     filemark 4461 kbytes
>>>>     speed 6272 kps
>>>> }
>>>>
>>>>         
>>> DAT tapetype reports have varied as to whether there was any
>>> filemark at all.  I don't know why.  My own testing on two
>>> HP DATs (dds2 & dds3) showed no filemarks.
>>>
>>> You might do another tapetype run to check if it is consistant.
>>>       
>> grunt:/usr/sbin # amtapetype -o -f /dev/nst0
>> Writing 512 Mbyte   compresseable data:  83 sec
>> Writing 512 Mbyte uncompresseable data:  83 sec
>> Estimated time to write 2 * 1024 Mbyte: 332 sec = 0 h 5 min
>> wrote 2437131 32Kb blocks in 7453 files in 28358 seconds (short write)
>> wrote 2096995 32Kb blocks in 12865 files in 40050 seconds (short write)
>> define tapetype unknown-tapetype {
>>     comment "just produced by tapetype prog (hardware compression off)"
>>     length 90796 mbytes
>>     filemark 2011 kbytes
>>     speed 2212 kps
>> }
>>     
> You skipped the -e option so amtapetype defaulted to a very
> small estimated capacity and wrote lots of small files.
> It probably was not streaming very well
>   
grunt:/usr/sbin # amtapetype -o -e 80g -f /dev/nst0
Writing 512 Mbyte compresseable data: 82 sec
Writing 512 Mbyte uncompresseable data: 94 sec
Estimated time to write 2 * 81920 Mbyte: 30080 sec = 8 h 21 min
wrote 2490330 32Kb blocks in 95 files in 12570 seconds (short write)
wrote 2477223 32Kb blocks in 189 files in 12780 seconds (short write)
define tapetype unknown-tapetype {
comment "just produced by tapetype prog (hardware compression off)"
length 78236 mbytes
filemark 4461 kbytes
speed 6271 kps
}

Seems consistent enough!

Thanks Jon and everyone else...

 
-- 
Rory Beaton
Telemetry/Instrumentation Group

Sea Mammal Research Unit      __)\      phone: 01334 46XXXX (office)
Gatty Marine Laboratory    .-'    `-.   phone: 01334 46XXXX (lab)
University of St Andrews  / .--, _   \  fax:   01334 46XXXX
Fife KY16 8LB  Scotland  / (  '-' ``--' web:   www.smru.st-and.ac.uk
                ~~~~~~~(,-'-,)~~~~~~~~~~~~~~~~~