[Techtalk] firewire

[Alvin Goats]

> Jaz discs, on the other hand, are much better, due to the fact that they
> use magneto-optical storage technology, and are thus inherently much more
> robust (unless you leave them sitting in direct sunlight, which will
> erase them after a time:).


Actually, they're a hard disk in a hardshell cartridge. They use hard
drive disk heads and have the performance of a low to moderate hard
drive. They are SCSI devices as far as I know (I only have 4 of them),
which would require either a SCSI port that a few laptops have or a SCSI
PCMCIA card. Personally, I use the Adaptec SlimSCSI which works just
fine, and can daisy chain up to 7 devices. It is an AHA-1542
archetecture (MINE is, at rev. D), so performance is not at a peak, but
quite serviceable.

The hardshell is black plastic which absorbs sunlight with very high
efficiency and heats up. The internal heat of the cartridge gets pretty
high and it is heat that removes the magnetism of the disk, scrambling
the data on the disk. If it gets too hot, the hardshell will warp
slightly, making the disk platter tilt and crsh the disk heads on the
drive. Those are the problems I've encountered over the years, but they
aren't that bad.


As for the 4 pin/ 6pin issue: most laptops will NOT supply outside power
to other devices due to problems with current drain on the battery (the
higher the current draw, the hotter the battery gets, the hotter the
battery the harder it is to cool the laptop and the CPU can overheat),
as well as customer complaints about a too short battery life. They
intentionally leave off the power pins to get around these issues. 


Alvin