Thursday, July 29, 2010

Hard Disks: Advantage of SATA over IDE

Hi everyone! I had asked a question in SM Lab Session (I don't even exactly remember the question now!) And I was told to 'Google it & Blog it'. So here I am blogging about IDE & SATA: Advantage of SATA over IDE.

Every hard disk is interfaced in the motherboard through a disk controller. This disk controller is the one that plays bridge between the hard disk and the operating system. For the user to access data from the hard disk, there is a data bus connecting the hard disk and the motherboard. The data bus is like a pipe where bytes of data are being transmitted.

There are two kinds of data buses, Serial ATA and Parallel ATA, which are used in SATA hard disk and IDE hard disk respectively.
IDE is the abbreviation of Integrated Device Electronics. (The Parallel ATA was earlier called IDE. That
s why hard disks that use Parallel ATA are called IDE hard disks.)

SATA stands for Serial Advanced Technology Attachment.

The concept of the SATA was ratified by the ANSI (American National Standards Institute) in year of 2002.


  • SATA has the capability to provide point to point channel communication between mother board and the drive. Where as in the IDE, the architecture of the master slave combination is supported on a single cable for the two drives it supports. (In the case of IDE, the controller allows the connection of 2 peripherals. The band-width is thus divided between the 2. This reduces the performances. On the other hand, in SATA, each hard disk is connected to its own controller via his own cable. This implies that there are no more bridging to configure for the main modes/slaves.)
  • The IDE hard disk drive uses the flat cable that has the width of around 18’’. But in the case of the Serial ATA a four wire cable is used that has a length of one meter. This is advantageous in comparison with the Parallel ATA (IDE) since the cables and the connectors that are used take less space than their counterparts in the Parallel ATA.
  • IDE platform is designed for normal / old computers, this way you transmit everything in parallel, and the IDE controller takes most of the work on transferring data.
    On Serial-ATA (SATA) the controller leaves most of the processing work to the CPU. (So if you have a small CPU you will prefer a IDE disk instead SATA, without mention that in old computers you will not have the SATA connector.)
  • IDE platform has it's top speed at 133 MB/s for ATA 133 (There is ATA 33, 66, 100 and 133) and for SATA you get 300 MB/s (SATA 1 have 150 MB/s, and SATA 300 MB/s).
  • Also, the SATA disk now are cheaper and bigger that any IDE disks.

Source: Various sites.
I have tried to be short & precise; have used simple language. Still queries n comments are welcome.

(PS: M blogging for the 1st time. please don't be too harsh!)


  1. Hey Nikita,
    Great post even if you are writing for the first time. Explained me the advantages well! :-)

  2. This comment has been removed by the author.

  3. Pretty nice article. Pretty detailed, but could've been slightly more. Looking forward to more posts from you.

  4. @apoorv, kshitiz, arjun: thank you all soooo much!! :) :D

  5. @Arjun: I will try to be more detailed next time... thanks!

  6. Hey dat was gr8..hope to see more from you..and if u find little time..can u give some detailed explaination of the 1st advantage?
    Thanx in advance

  7. hey niks!i really liked your post.i came across another point in support of SATA.i'd like to share it with everyone:
    the sata interface has the ability to hot swap drives. Hot swap means that you can pull your drive from your machine and replace it with a different disk without restarting your computer. This will especially be helpful for people who are not familiar with configuring a RAID array for backups.

  8. @arjun ahuja: I will get back to you shortly with more details.
    @sakshi: thanks for update! Can you please elaborate 'Raid array'...?

  9. Hey Nikita
    The blog post is really good. I being a person having no knowledge about this stuff, found it quite interesting and easy to comprehend. Keep up the good work. :)
    It is a masterpiece. :P

  10. @Karan: Thanks a lot!
    Ahhmmm... "Masterpice" line was toooo much to handle... But thanks! :p :p :p :D

  11. Hot-swapping without redundancy systems (like RAID) may cause major loss of data. Don't try it at home.
    Also, RAID is a pretty extensive topic in itself. Anybody willing to volunteer to write a blog post on this? :P

  12. i'm willing to do it but i need "contributor" status first before i can put up a new post :\

  13. @Arjun Ahuja: As i said in SATA, each hard disk is connected to its own controller via its own cable. On the other hand, to allow for two drives on the same cable, IDE uses a special configuration called master and slave. This configuration allows one drive's controller to tell the other drive when it can transfer data to or from the computer. What happens is the slave drive makes a request to the master drive, which checks to see if it is currently communicating with the computer. If the master drive is idle, it tells the slave drive to go ahead. If the master drive is communicating with the computer, it tells the slave drive to wait and then informs it when it can go ahead.

    Hope the 1st advantage is clear now... :)

  14. Shayan, if you've given your GMAIL ID in the sheet that was passed around in the first class, you've been sent an invite. Check your email. If you still have any problems, email me, and I'll send you another invite.

  15. heyy..nice blog..& the language is actually very simple(as compared to the other blogs)

  16. @Arjun- got it. gonna put up the post soon

  17. very informative blog in a simple language..i did not really understand this stuff then but your blog cleared my doubts:)..

  18. So let me get this straight - SATA is cheaper, faster and takes up less space. And doesn't divide bandwidth, so doesn't cut down on the performance. But IDE is suitable when the CPU isn't very big.
    Is that right?

    Not bad for a first attempt btw! :)

  19. @Shipra: Thanks! Good to hear that! :) :)
    @Espèra: Yeah! You got it right! Thanks btw! :D