29 Apr

In earlier days, it was a technological battle between IDE and SCSI. These days its a three way battle of SCSI vs SATA vs IDE. The following article is going to highlight the current trends in this technological battle for supremacy

The following article ‘SCSI vs SATA vs IDE’ is going to explain various details of these data communication interfaces. The competition between the three is at its zenith right now. It should be interesting to see what future lies ahead for these interface standards.

IDE Explained
Integrated Drive Electronics(IDE) has a history of gradual development. After going through many technological advancements, it has evolved into what is today known as PATA. The underlaying standard for IDE is AT attachment and hence the name PATA. The name PATA has been the retronym for IDE since the introduction SATA. In IDE standard, the cable length is limited to 460mm. Because of this, most of the devices that use IDE are internal to the computer. Before the advent of SATA, IDE was the most inexpensive and widely available standard in market. But SATA , in recent times has gradually captured IDE market.


SCSI Explained
SCSI is pronounced “skuzzy”. Now that is out of the way, here is the technical explanation. Every computer needs to be connected with peripheral devices once in a while. Basically, peripheral devices are those devices that are connected externally to the computer. Now where does SCSI fit in over here? SCSI is set of standards that are used to communicate with the peripheral devices. These standards are also used while transferring the data between computer and external devices. SCSI is generally used for communicating with hard drives. It is also used for communicating with other peripheral devices such as USB flash drives, CD ROM, printers and many data storage devices.

Consider a situation. There are three desktop computer hosts which need to use five peripheral devices. Now how will these hosts communicate with peripherals? Here a need of common platform arises. SCSI interface has been developed to provide such a platform. An important obvious thing I feel the need to mention over here is that, there has to be at least one host for any number of peripherals. SCSI interface is mainly used for hiding the complexity of the underlying physical format.

SATA Explained
If you think SATA is any different than SCSI or IDE, well their end result in functionality is pretty much the same. Just as SCSI is different from IDE, SATA also has some of its own characteristics. SATA is an acronym for Serial AT attachment. The work on SATA began with an aim of replacing the older IDE technology. The developers of SATA interface were successful in using the same commands that were used for IDE. As explained above, IDE is a parallel technology, while SATA is a serial technology. SATA also has an IDE emulation mode, which means that SATA interface can operate as IDE, if the computer motherboard is of old technology and does not support advanced host control interface. Basically its the PATA mode. Read more on hard drive types

SCSI vs SATA vs IDE: Reliability
In the context of comparison, SATA is significantly more reliable than IDE. If the comparison has to made between SCSI and IDE again SCSI is far more reliable than IDE. SATA has already left IDE behind, now it is gaining major grounds against SCSI.

SCSI vs SATA vs IDE: Performance
Continuous research on all three interfaces has increased their performance, but SATA has shown to be the most promising of all. SATA has greatly improved its performance in recent years, but SCSI has not been able to match such increase. SCSI is still out performing SATA, but it had high performance to begin with. SCSI still remains on top of the three interfaces, but the coming versions of SATA should out perform SCSI.

I hope that the above article on SCSI vs SATA vs IDE has shed light on their key differences. But in my opinion SATA interface would be the leading industry standard in years to come.

this is my refrence


Hello everyone,
Would like to hear from your experience on this.
I believe that scsi 10k are far better than sata 7200 in overall performance (read, write, response etc.).

Is that right?
And why so many servers are using sata nowadays? Wouldn’t compromise on performance?


scsi is faster, but scsi costs more, its all about balance. Do you really need the extra speed scsi will give? Can you afford the difference it will cost? ETC. Also other things may be more important such as space. For example you could get 4 2tb sata in RAID10 for the ~cost of a couple of 450gb scsi. The SCSI may be faster overall, but the sata will be catching them up and have over 4 times the space available. If you want best speed without factoring cost, then (in most cases) perhaps you should look at ssd?
It’s largely to do with how fast the disk spins.
If you have a disk spinning at 15,000 RPM, your seek times are going to be more than half of those of a 7200 RPM drive.
If your system’s workload is mostly random read/writes, you are virtually going to need a seek for every random I/O operation.

I don’t think this has much to do with the interface (SATA vs SCSI) – the new SAS interfaces deliver more than the adequate amount of bandwidth in a serial connection. A drive spinning at 15K is always going to be more expensive than a drive spinning at 7.2K RPM due to the physics/mechanics involved.


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Posted by on 2010/04/29 in Uncategorized


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