From Wed Mar 20 11:33:47 2002
Date: Wed, 20 Mar 2002 11:32:49 -0800
Cc: Niall O Broin
Subject: Re: [ILUG] backup options...
From: Rick Moen

Quoting Niall O Broin (

> Ultrium (as previously mentioned) has 100GB native capacity, drive
> costs $3000 (best price on pricewatch, so you'll probably pay somewhat
> more) and cartridges are $85 + - claims to backup 108GB per hour which
> is of course with mythical compression of 2:1 so actually claim is
> 54GB / hour which is 15 Mbyte/second which is pretty nippy :-) I read
> on review of this which said that the speed claim is not marketing
> bullshit and that it is actually very fast.

LTO ("Ultrium") is pretty damned good. For those who can afford the price of admission. <sigh> In its class, you have SDLT and damned little else.

One point of comparison is of course helical scan vs linear vs. other. As noted previously, helical scan wears tapes and heads rapidly.

Media type  Head type          Nom. capacity  Nom. speed  Vendors
8mm         helical scan       2GB/5GB        500kB/s     Exabyte, Tandberg
"AME" 8mm   helical scan       20-60GB[1]     3 & 8MB[2]  Exabyte 
DLTtapeIII  linear serpentine  10GB
DLTtapeIV   linear serpentine  20-40GB        3-5MB/s     Quantum, others?
DLT1        linear serpentine  40GB           3MB/s
DLT3XL      linear serpentine  15GB           1.5MB/s     DEC, Quantum
DLT7000     linear serpentine  35GB           5MB/s       Quantum
DLT8000     linear serpentine  40GB           6MB/s       Quantum
DLTtape VS1 linear serpentine  80GB
SuperDLT    linear serpentine  110GB          11MB/s      Quantum, Tandberg
DDS2        helical scan       2GB/4GB        500kB/s     HP and others
DDS3        helical scan       12GB           1.5MB/s     HP and others
DDS4        helical scan       20GB           2.4MB/s     Various
VXA-1       linear serpentine? 33GB           3MB/s       Ecrix
AIT         helical scan       25-50GB        6MB/s[3]    Sony
AIT-2       helical scan       50GB           6MB/s       Sony
LTO         linear serpentine  100GB          16MB/s      IBM, Seagate, HP
ADR2        linear serpentine  120GB          5MB/s       OnStream

Also relevant: Cost of tapes, cost of drives, cost of replacement heads, service life....

Be sure to consult The Linux Tape Device Certification Program, before buying any drive:

[1] When used in M2-type drives. M1 does 2.5-20GB.
[2] Thanks to Ray Kelly for furnishing AME speed figures.
[3] That's with AIT2 drives. AIT3 drives do 12MB/s, with 100GB capacity.


Cheers,     "Learning Java has been a slow and tortuous process for me.  Every 
Rick Moen   few minutes, I start screaming 'No, you fools!' and have to go       read something from _Structure and Interpretation of
            Computer Programs_ to de-stress."   -- The Cube,