IDE v. SCSI

[strredwolf]

I now get to wonder...

The old Toshiba Satellite 115CS's PCMCIA cards can't do CardBus, and Linux doesn't support DMA on PC Cards (16-bit version of Cardbus).  This is due to the laptop not being PCI based.  So, any IDE or SCSI PC Card I shove in there is stuck at PIO (Programmed IO) speeds.

With IDE, the main CPU has to take a bit of attention to work the controller and get things right.  Cheap, but intensive.

With SCSI, the CPU just needs to say "HEY!  THIS unit, THIS logical unit, THIS head, track, and sector, THAT many, and tell me when you're ready."  A second CPU takes that, translates it to the drive, grabs it, flags the CPU, and hands the info over.  Expensive, but relatively fast.

I'm wondering what's faster over that PC Card interface...

Comments

[kisai.livejournal.com]

consider that "ISA" technology runs at around 8Mhz, not 33Mhz like PCI. Chances are you are not going to get anything faster than 10MB/sec off the expansion card slot.

PIO mode will sap the CPU, so may as well not even bother with the expansion card slot.

unless you can find something interesting on a port replicator that has SCSI, or the laptop has as IEEE1394 port, you aren't getting any faster.

*currently has a Toshiba Sattelite P10*

[strredwolf.livejournal.com]

Given that it's only ISA, and it's using PIO, I'm thinking more protocal differences (how much manhandling IDE does versus the simple request nature of SCSI).