Hard Drives

[mbritton2]

what are the diff between IDE ,SCSI ,and SATA

[John Prophet]

IDE is the most standard type of drive..it uses the 40 pin ribbon cable

scsi is a more expensive type of drive usually found in servers..there are lots of different "flavors" of scsi (very confusing to me, lol)

sata is the newest type of interface....it doesnt use ribbon cables..it is a little faster than the IDE interface

[no1_vern]

IDE stands for Integrated Drive Electronics. SCSI stands for Small Computer System Interface. A hard drive is either an IDE/EIDE/PATA/SATA drive or a SCSI drive. EIDE and PATA/SATA are further developments of the IDE. In other words, IDE, EIDE and ATA/SATA function in much the same way, whereas SCSI is quite different.
Most hard drives are IDE/EIDE/ATA/SATA. The reason for this is that IDE drives (and EIDE/ATA) are cheaper, giving them an obvious advantage; you get a large-capacity hard drive at the same price.

The advantage of the SCSI is that it's better for multitasking. It's possible to read and write to the drive at the same time, while running other programs. It has less impact on the microprocessor. In addition, it's an advantage that one SCSI controller has room for up to seven disks, whereas an IDE controller only has room for two. A SCSI cable can be up to three meters long. An IDE cable can only be 0.5 meters long. The length of the SCSI cable makes it easier to place the SCSI disks outside the PC case. SCSI has a tagged command queueing implementation so that multiple commands can be queued - providing another performance enhancement. This is handled by an interface processor on the SCSI contoller which is separate to the processor that controls the head positions. On ATA, these duties are shared by a single processor.

Due to the advantages of the SCSI, this is the most common drive in network servers. But in ordinary workstations IDE/EIDE/ATA/SATA is the most common.

Some good info:
http://searchstorage.techtarget.com/...935636,00.html

While its cheaper to buy IDE/ata/sata, you are trading reliability for cheapness and for my information that just wont do.
I believe that SCSI is still the most RELIABLE and arguably the fastest interface available to use.

Quote:
SCSI, U320 (especially the 64-bit variety) is more than twice as fast as SATA 150 in measurable terms, and in usable terms wipes the floor with it like a Ferrari overtaking a Ford Ka. SCSI is also hot-swappable, so if a disk in an array fails there is no real panic. If you need to swap a disk in an SATA array (and consider this if you're thinking of a 6Tb array), you run the risk of system crashes, according to THG, and it is currently NOT hot-swappable.
<snip>
It is rare in the extreme for anyone to use IDE RAID in a server. Every server I have ever bought has depended on SCSI over IDE. In fact, I don't know of a single company that would consider using IDE (ATA) in a server. But that's just me and the companies I deal with.

A SCSI RAID controller will also have a cache. Some non-RAID controllers do. Anything from 2Mb to 256Mb and beyond. This is in addition to the drive's cache.

For desktop duties, SATA is superb and econmical. For high-speed, dependable servers, SCSI is still the only choice.
FRom: http://www.tek-tips.com/gviewthread....602/qid/775673

Serial Advanced Technology Attachment (SATA) and Serial Attached SCSI (SAS). SATA and SAS are point-to-point connections for attaching the PC to internal or closely located storage.

White paper on ata vs Scsi: http://www.usenix.org/events/fast03/...anderson_html/

Hope this helps.

[mbritton2]

Thanks for all the info

[roley]

To me the salient features of the differences between the different hard drive interfaces is their speed and multitasking ability.

ATA-100/133 is fast enough, but is not so good for hard drive intensive job (eg servers)

SATA-150 is faster and if you get the new Western Digital Raptor, does have higher performance SCSI type features. (I have built system with this drive...runs very quick)

SCSI (U160/U320) is the ultimate hard drive on the market. It has the highest peformance in multitasking environments and data intensive applications like video editing etc. And when assembled into (R)AID configurations it is miles ahead of ATA systems.

However, SCSI comes at a premium. If you do not mind paying for it, SCSI is excellent. Both my office workstations run Adaptec 19160 based SCSI systems (Cheetah 10KRPM drives with ATA storage drives for critical data.


if you have a new board that supports SATA...I would suggest that. If you have plenty of money...[......] then I would advocate SCSI.

Anyway, in the end you do what you can afford and what you know.

Rohan