Karbosguide.com - Module 5b2b.

RAID/EIDE controllers

The contents:

  • The Promise FastTrack EIDE controller
  • Adaptec UDMA RAID
  • Highpoint UDMA RAID onboard

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    • The Promise FastTrack EIDE controller

    You may expand your system with a little PCI-based EIDE-controller from Promise.

    This controller can be connected to two or four EIDE hard disks. And it works side by side with the existing EIDE-controller on the motherboard! I have tested it, and it works fine:

    FastTrack

    The card is very powerfull. You can use it in multiple setups:

  • Connecting four EIDE hard disk to your PC; the onboard EIDE-controller can be used for CD-ROMs, ZIP or other ATA-based drives.
  • Increased performance (2X or 4X) by using the RAID 0 functionality.
  • Increased capacity since two or four disks can be assigned to one big virtual drive.
  • Increased security using RAID 1 mirroring.

    The most impressive thing is that the controller holds its own BIOS. It works complete independent of the hosting PC.

    Striping

    The FastTrak controller can double or quadruple the transfer speed if you want it.

    Using RAID 0 striping, the data are striped over more than one drive. You use two or four identical drives, which all are unified into one big volume.

    When you write data to the drive, it is simultaneously written to all two or four drives in the array. This is the principle of striping: interleaving during the read/write process.

    The stripe size (blocks to be striped) can be set from 1 KB to 1024 KB. The default value for business application use is stripe size 8 KB. For working with bigger files (for instance sound and video editing) the recommendation is 64KB.

    Mirroring

    Using RAID 1 mirroring, the data are duplicated to several drives. This gives an increased security. The system is fault tolerant; if one drive is damaged, the data can be read from another.

    My own use

    I was very glad to use the FastTrack PCI RAID controller. I used it just to improve the capacity of the EIDE system.

    The PC looked like this regarding EIDE units:

  • Motherboard primary EIDE, master: A 28 GB Seagate hard disk, 7200 RPM.
  • Motherboard primary EIDE, slave: Nothing.
  • Motherboard secondary EIDE, master: A 40X CD-ROM drive.
  • Motherboard secondary EIDE, slave: A HP 8100plus CD-RW drive.
  • FastTrack primary EIDE, master: A 30 GB Maxtor hard disk.

    The two hard disks (each formatted into just one big partition) cooperated very well. I could copy between them at 10 MB/sec.

    With the system described, I had room for expansion, since I could add another disk to the FastTrack secondary master. I could also have opted for stiping, if I'd wanted to - it only requires two identical disks. I have tried it, and it works fine.

    The FastTrack adapter can stripe disks for better performance, but as described here, it is also great just for adding versatility to your PC system!

    Adaptec UDMA RAID

    The name Adaptec has for many years been synonymous with SCSI and SCSI-based RAID.

    The AAA-UDMA RAID controller supports up to 4 ATA/66 hard disks in RAID 0,1, 0/1 and RAID 5 (fault tolerance) arrays. The RAID 5 array is interesting for use in servers, giving the option of hot-plugging a substitute disk in case of diskfaults. All data is reconstructed on the fly.

    This is the first time that this is possible using EIDE disks, and it shows how the quality of the EIDE/ATA standards is improving nowadays.

    The maximum output of the RAID controllers is 66 MB per second due to the limitation of the ATA/66 protocol. With ATA/100 and later Serial ATA we shall see much more powerful systems!

    RAID controllers on the motherboard

    In 2001 we saw several motherboards including ATA/100-based RAID controllers onboard.

    I bought an Epox 8KTA3+ board for my 900 MHz AMD processor. Overall, it is a very nice board, but the best feature is the ATA/100-based RAID controller which is integrated.

    The RAID controlling logic comes from HighPoint; their HPT370 chip is located on the motherboard:

    Here it cooperates with the traditional "south bridge" from VIA:

    Together they control four EIDE-channels all ATA66/100 compatible:

    This way you are free to assign up to 8 IDE units to the motherboard. Most people would probably have two hard disks and two CD drives. With this board they can be mounted as master on each channel. That is really good!

    With Windows , you always get RAID controllers recognized as SCSI controllers. This is also the case here. Installing Windows 2000 or XP using the HighPoint controller, you have to use the driver diskette included with the board. It's a little bit weird why these Windows NT-based OS's cannot detect a RAID controller and install a driver automatically.

    However the driver installation works perfectly. You see the controller under SCSI/RAID controllers:

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    To learn more

    Read more the boot process and system bus in Module 2b

    Read about file systems in module 6a

    Read about I/O buses in module 2c

    Read about the motherboard chip set in module 2d

    Read about RAM in module 2e

    Read Module 5c about SCSI, USB etc.

    Read module 7a about monitors, and 7b on graphics card.

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