[ILUG] backup options...

[Padraig Brady]

There is also the speed issue to consider.
Can anyone extend this table with DDS[1-4] etc. speeds?

thanks,
Padraig.

-----------------------------------------------
Interconnect      Max Speed in M Bytes per second
-----------------------------------------------
4X CD               0.6
10Mb/s LAN          1.2
100Mb/s LAN        12.0
USB                 1.5
USB 2.0            60.0
Firewire           50.0
Firewire b        100.0
PIO  Mode 0         3.3
PIO  Mode 1         5.2
PIO  Mode 2         8.3
PIO  Mode 3        11.1
PIO  Mode 4        16.7
DMA  Mode 0         4.2
DMA  Mode 1        13.3
DMA  Mode 2        16.7
UDMA Mode 0        16.7
UDMA Mode 1        25.0
UDMA Mode 2        33.3
UDMA Mode 3        44.4
UDMA Mode 4        66.7
UDMA Mode 5       100.0
SCSI-1              5.0
FAST SCSI          10.0
Ultra SCSI         20.0
Ultra2 SCSI        40.0
Wide Ultra2 SCSI   80.0
Ultra3 SCSI       160.0
Ultra320 SCSI     320.0
ISA                 8.0
Parallel            0.1
PCMCIA             20.0
CardBus           132.0
PCI 2.0           132.0
PCI 2.1           264.0
PCI 2.2           528.0
-----------------------------------------------

Note Ultra DMA does not support overlapped seeks,
bus bandwidth sharing, or command queuing/reordering
because of its single-threaded nature. Also disks are
a limiting factor as opposed to bus speeds. Usual actual
speeds are UDMA/2 = 9MB/s, UDMA/5 = 18MB/s, UDMA/5 = 27MB/s.

Niall O Broin wrote:
> On Wed, Mar 20, 2002 at 10:16:43AM +0000, Liam Bedford wrote:
> 
> 
>>Well, 20 megs uncompressed maybe, if you're talking about 25 years ago.
> 
> 
> In the days of 80 character terminals, then ?
> 
> 
>>AIT-II is 50G native, AIT-III is 100G native...
> 
> 
> and Ultrium is even more, I think - google if you're interested.
> 
> 
>>(interestingly, the compression ratio's they quote seem to be growing...
>>they used to quote 2:1, now they're doing 2.6:1).
> 
> 
> This REALLY bugs me - I remember doing an informal survey on sun-managers
> years ago and real world compression ratios to Exabytes or DAT were about
> 1.4-1.6:1 and I seriously doubt that there's been some new magic streaming
> compression algorithm found.
> 
> 
>>Though you are looking at a substantial investment for both of those tape
>>drives, with a < 10% duty cycle IIRC. The tapes run between 40 and 100 EUR,
>>depending on capacity.
> 
> 
> Assuming 100 EUR for 100G, that's still somewhat cheaper than IDE - best I
> can see with a quick look is 111.50 EUR fro a 60GB Maxtor drive.
> 
> 
>>DDS4 is 24G compressed isn't it? I know with my usage, that would cover the
> 
> 
> No - DDS4 is 20 GB native - DDS3 is 12 GB native. They claim 2:1 compression
> - I claim immortality - both claims equally spurious.
> 
> 
> 
> Niall
>