OT: SLR 5 Tape drive vs DAT

[Bill Akers]

Bill Vermillion wrote:
> As Bill Akers was scratching "For a good prime call 
> 391581 * 2^216193 -1" on the wall, he suddenly said:
> 
> 
>>Kenneth Brody wrote:
>>
>>>Quoting Scott Walker <scottw1 at alltel.net>:
>>>
> 
> 
>>>>One of my customers has an old QIC tape drive that has finally died.
>>>>
>>>>I told him to get a quote on a DAT drive to replace it.
>>>
>>>[...]
> 
> 
>>>Nowadays, is there any inherent advantage of using tapes when
>>>DVD writers and media are getting so inexpensive?
> 
> 
>>There is the advantage of having media large enough to store   
>>all files in one pass. And even if you span the DVD's there    
>>is the cost of someone's time to attend to the DVD writer      
>>and change the media. And there is the time to erase the DVD   
>>manually if you are using RW media.                            
> 
> 
> Part of that will depend on your SW - sometimes you can just
> overwrite.   And with +RW media the quick erase is typically only
> about 10 seconds while the -RW media can take well over a minute.
> 
> The simpler design of +R/RW means cheaper manufacturing and
> manipulation than the original -R/RW.  Erase time in the +RW arena
> isn't a big factor IMO.
> 
> I'm just finishing going through the second case of DVD cases
> [totall of 200] converting 20 years worth of video into a DVD
> format - so I've gotten more than familiar with this - going
> through at least 4 disk per day.
> 
> 
>>Tapes generally run unattended with about a total of less than 5 
>>minutes a day to change our and store the tape for two servers, 1 
>>Windows and 1 Unix. This is thousands of dollars difference in a year 
>>alone, without considering the life of the server.
> 
> 
> And that is something too many people forget to factor in.  The
> total cost over a year.  I spec'ed one machine for an exec at a
> client site - as they were typically buying the bottom line
> machines - and though the one I spec'd was about $400 more it was
> that much faster - and know what the person was doing - that
> machine would actually save them money in a years time as I was
> seeing a minimum of 30 minutes lost time per day on the slower
> machine.   That's 2.5 hours week or 125 hours per year.

I did a rough analysis of the cost of using DVD for backups versus 
tape about a year ago, when we put in a new Windows server, and 
concluded that it ws more costly than it initially seems. I have not 
seen software that, in my understanding, would overwrite a DVD without 
first erasing it, so I included the erasing as a factor. The cost of 
the hardware and media was significantly less than scsi DAT 
tape(hundreds of dollars), but the labor cost of the employee attended 
  backups using DVD was thousands(estimated $3000+ not including 
perks) of dollars more over a year. I looked for the analysis, but I 
think it disappeared when I gifted myself with a new computer.
Something we did not anticipate at that time has come to light that 
makes DVD backups even more of a problem for us is that engineering 
drawings stored on the server could be open for hours while they are 
being modified, causing the backup to stop and wait for the drawing to 
be closed.
Also relevant was that the backup could not be made during the night 
as the automated tape backup could be, meaning that possibly a DVD 
backup set could either have files that were not necessarily 
concurrent(people updating files while the backup was being made) or 
if it could be set to skip open files, would be incomplete as files 
would be missing; both of which scenarios are unacceptable. A 
multilayer drawing with one or more layers out of sync with the others 
or with a missing layer is considered by us to be catastrophic(heads 
may not roll but nervous hablts will develop such as twitches and 
jerks as people attempt to make sure they are not the reason the event 
occurred).

> 
> Looking at the all the overhead of an employee, the taxes,
> insurance, etc added onto the basic wage that is easily $2000 -
> $3000 year wasted.
> 
> I know how that is as one place I worked part-time gave me an
> office to work in and one of the slowest machines.  I figured
> out the time I spent wating was costing them and addition
> $50 - $75 per week - and I HATE waiting on machines.
>