Different hard drive terminologies?

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I have come across terms like SATA, SCSI and SSD. Can somebody please elaborate the differences between these terms based on their technology and more importantly applications and industry trends?

Shurmajee

Posted 2012-12-19T11:33:39.340

Reputation: 410

Question was closed 2012-12-19T16:28:05.233

2SCSI -> Server oriented disks drives, SSD are drives made from flash memory chips (MLC/SLC) that have no moving parts. Used for high-end computers. Have realy Big transfer speeds and read write speeds. Expensive in relation to their capacity. HDD/SATA - spinning disk drives. Best price in relation to their capacity. – mnmnc – 2012-12-19T11:41:50.797

2@MayankSharma 1. [su] isn't a forum 2. It's expected that some basic research has been done and shown in the question – Sathyajith Bhat – 2012-12-19T13:15:47.417

Answers

7

This seems almost like a homework question ;p

Firstly there's two main types of storage - hard drives and SDDs

With hard drives, in general there's two things to look at - first is RPM - higher RPM is faster, but noisier and uses more power. The second is cache, more cache is generally better, and results in better performance.

With SSDs, information is stored on flash chips, usually NAND. In addition to transfer speeds, you'll want to look at SLC (fastest, longest lived, most expensive, usually used in enterprise grade drives), MLC ('normal' flash storage) and TLC (uncommon at the moment, supposed to be cheaper, has the worst life). Most SSDs are faster than even the fastest hard drives, but the trade off is smaller capasities and higher costs.

Secondly interfaces.

Older devices (well, within the last 20 years or so) used IDE/ATA, which has been bacronymed to PATA or parallel ATA or SCSI. SCSI had multiple varients, and often needed terminators. Different types of scsi drives were incompatible with each other.

Modern devices usually use SATA (or Serial ATA) or SAS (Serial Attached SCSI). With Sata we have 3gbps and 6gbps ports - use 6gbps ports for SSDs and 3gbps ports for hard drives.

With SAS one type of connector is sata compatible (if the chipset supports it) while the other two arn't. SAS drives tend to be classed as nearline (cheaper, slower drives, though often better than consumer drives), and classic drives.

If you're using consumer grade gear, go with sata. If you're running a server go with SAS. If you're expected to use IDE or Scsi in this day and age... well, you're running a museium of old computers.

Journeyman Geek

Posted 2012-12-19T11:33:39.340

Reputation: 119 122

Well i am just a beginner... – Shurmajee – 2012-12-19T12:06:07.260

You shouldn't lump/connect PATA and SCSI together. SCSI is still a useful ( today ) in some limited applications. PATA was retired because of the limitations of the bus itself. It was simply replaced by SATA for those limitation reasons. – Ramhound – 2012-12-19T13:23:49.563

Should I be worried that we just recently purchased a couple of ~70GB SCSI drives? :P – Bob – 2012-12-20T07:48:37.277

Well if you need it you need it. I'd just not expect SCSI on modern equipment. I'd just hope you got the right sort of scsi since there are a lot of different, incompatible varients ;p – Journeyman Geek – 2012-12-20T07:50:15.603