IDE Co-Processors?

morbid asks: "EIDE is generally considered to be inferior to SCSI because it requires more involvement from the processor slowing the system down, but would it not be possible to build an EIDE/ATA (?) controller with its own processor, freeing up the CPU and increasing system performamce while allowing the use of inexpensive drives?"

Comments

SCSI & Multi-tasking OS's

[maggard]

Well, SCSI is a bit more then a fast way of talking to a drive. It also frees the CPU from many of the drive geometry issues that it would otherwise have to track. SCSI also allows things like multiple devices per channel, request queueing, smarter IO, disconnect/reconnect, etc. These features aren't likely to show up in EIDE drives simply because adding them would cost the same as SCSI and why reinvent the wheel?

Right now the next step in consumer high-speed drives appears to be Firewire/iLink/1394 (depending on the vendor.) USB 2.0 has just appreared in silicon but it's already slower then Firewire/iLink/1394 and not as flexible. Intel is also working on PCI/X as a next generation replacement for the now venerable PCI bus. They appear to be going to a serial-bus design with smart interconnects.

One well regarded scenario for the future of PC's has them turning into black boxes containing little more then a CPU and graphics card. Everything else would be handled through high-speed serial connections.

3Ware's ATA-RAID controllers do just that!

[BitMan]

Forget Promise, SIIG and others. 3Ware's Escalade series of products are just what you are looking for. Keys to performance with Escalade:

• On-board co-processor that acts like a SCSI target from the standpoint of the OS/driver. The same you'll find on most SCSI RAID controllers (i960 or similiar). This dedicated CPU drives your CPU, not your mainboard chipset's southbridge (which normally requires some CPU overhead even with bus mastering).
• One IDE drive per-channel. No "slave" issues. 100% Hot-Swap capability (although you'll need a IDE hot-swap bay/chassis for full hot-swap capability). Maximum performance.
• 2-8 channel boards, roughly $50-60/channel -- not much more than those crappy Promise FastTrak cards, only much, much faster.
• 100% Linux support. 3Ware controller support is built-in to most newer 2.2.x kernels.

If you want to minimize cost and performance, 3Ware's Escalade is what you want. Their new 6000-series offers 2-8 channels of RAID-0/1/1+0 with Ultra66 support for $139/279/479 (2/4/8 channel).

3Ware is also working on a 64-bit PCI board with RAID-5 support (as well as Ultra100). Be looking out for it (I know I will).

-- Bryan "TheBS" Smith