filmscanners: scanning/photoshop workstation (long)

["PAUL GRAHAM" <peegee@btinternet.com>]

Hi all,

I've been researching for months about getting a medium format workstation
for my scanning work, and thought I'd just run it by the forum for opinions,
oversights, have my assumptions corrected, and perhaps even be some help to
others too.

Basically the new 4000 dpi m/f scanners will output such large files that
handling them demands a new ball game in desktop systems: files of 500 to
700 Mb will be common at 4000 dpi, (in 16bit), and no doubt 6000 dpi will
come along soon for 35mm. If you do 5x4" - god help you.

Processing power is not the problem, a high end Mac, P4 or AMD Athlon, will
all do the job well. All of these have enough power/ MHz. The issue seems to
be the memory handling of these large files:

Now, the rule of thumb is that you need 3 to 5 times the RAM as your file
size for efficient PS handling, so... this means maximum RAM on the machine:

Max RAM for any programme in a Mac OS is 1Gb (out of 1.5 Gb on the board)
Max RAM in W 2K is 2Gb per programme (out of up to 4Gb)
so this means... a Windows machine, until Mac get their motherboards
upgraded.

ok: from what I understand the max RAM controllable on a windows board is
set by the chipset, and of course, the physical number of memory slots
present. Older chipsets/boards are pretty much the same as Mac's (3 memory
slots (dimms), 1.5Gb controllable) But there are now motherboards out there
now that have new chipsets (3 or 4 Gb controllable) and 4 memory slots, so 2
Gb is can easily be dedicated to Photoshop alone.

Newer DDR memory boards (latest Athlon systems) are also out there with 3 or
4 slots, as are P4 boards, with Rambus memory RIMMS, but... this memory is
very expensive, with a 512Mb stick being about $800 in DDR compared to only
$170 currently in the older SDRAM. so.. if you are buying four of these (to
make 2Gb) then you can save literally thousands of $ by not buying the
latest memory types, losing maybe a few % performance. Or put another way,
you can have 2Gb of SDRAM for the price of 500 Mb or DDR RAM.

It seems a new style Athlon SDRAM board with 4 slots is the way to go for
best bang per buck at present.

(Incidentally, 1 Gb sticks are much more reasonable than they were - but
this means they are now $1400 rather than $6000.... so forget about them.
They are also only available in the older SDRAM format anyway)

Whatever happens obviously you are going to run out of RAM eventually, and
be writing to the hard drive... so fast hard drives are essential, and RAID
seems to be coming in as the new standard for all workstations. That is, in
its simplest performance mode, writing/reading your data across two or more
drives (stripping, or RAID 0), which gives dramatic speed improvements and
memory handling, apparently. This used to be SCSI territory, but now ATA
RAID (for regular drives) is common, and RAID controllers are included on
many windows motherboards, so it is just the cost of the extra drive.
(cheap).
so, you could get two good IBM 75 Gb drives, which makes 150 Gb of stripped
UDMA memory for about $600 ($300 x2).
SCSI RAID would be faster still, but this, for 150 Gb, would be $1800 ($900
x2) plus a controller $250, (though sometimes even SCSI RAID is included on
high end boards) - pricey, but possible for a very quick system, or as a
substitute for lower RAM.

(Incidentally, you can get an ATA RAID card for Mac's too, but they don't
push it as Mac would rather sell you SCSI for high $. This could make the
MAC system workable with only 1 Gb photoshop memory, for not too many $
extra)

So that is where I am at, and about to spend my hard earned dosh.
Sorry if this is geek-speek to some, but others will (hopefully) point out
some mistakes or oversights in my thinking, and advise another way...
please.

I know this sounds crazy high-end stuff, but I really think its coming in
thick and fast... there will be plenty more pro-photographers out there
doing this same m/f scanning, and all coming up against these issues.

regards to all,

paul