IDE interfaces.
Most computers (and now devices like Xbox ) contain hard drives, CDROM and DVD drives connected via IDE interfaces.
There are now two types of IDE interface to consider. SATA and the old style PATA, aka ATA, IDE or even UDMA.
The new type is SATA. SATA means Serial ATA.
The older type is ATA or IDE, or PATA. PATA means Parallel ATA.
Executive summary for ATA , IDE, PATA
IDE stands for “Integrated Device electronics” the reasons for that are historic.
IDE is also known as ATA, UDMA, UDMA33, UDMA66, ATA66, ATA10, ATA133 and PATA. PATA for Parallel ATA.
ATA33, ATA66, ATA100,ATA133, UDMA, UDMA 33, UDMA 66, all refer to Parallel IDE type drives, where the drive can talk to the interface (and therefore the host computer) using the bus mastering DMA protocol. The maximum speed of the transfer is given by the number (in MHz). Actually the first bus mastering IDE devices ran at 16Mhz, but no one ever called that “ATA16” .
There are Rules are for Parallel IDE devices.
* Speeds of UDMA 66 MHz and faster require an 80 conductor cable. Speeds of 33MHZ can run fine on 40 conductor cable.
* Dont disable DMA on an interface or else it will be running at a maximum of 1 Megabyte a second. DMA is good. UDMA is better.
* one END of the cable should plug into the IDE interface at the motherboard or card. * If there is one device on an IDE cable, it should go at the END. * If there is one device, it should be master - but you can get away with *CDROM* and *DVD-ROM* (not burners) as slave on its own.
* You cannot get away with hard drives as slave on their own.
* You can still get incompatibilies between devices. If two drives are having trouble on the same interface, swap the master slave status around, or swap them to another interface.
* You can use Cable Select (CS) settings on the devices when you have a Cable select cable. A cable select cable should have the end connector labelled as MASTER and its middle connector labelled as SLAVE. A drive that is set to cable select becomes MASTER if you plug the MASTER connector into it. ( etc for SLAVE)
* You can use the devices jumpers to override the cable select cable settings.
* You dont need to have a drive in BIOS for it to work. You only need the boot drive in bios in order to be able to boot. Windows 95, 98, ME, NT, 2000, XP and Linux, Freebsd, etc will all find the other drives.
* You do have to turn on the interface in bios, because if you turn an interface off, the interface doesnt respond when spoken to. “secondary interface: enabled” is a good idea :)
* Some computers lock up when you put a large hard drive into it. (larger than 32 gigabytes) This is TROUBLE. Most drives can be set to be 30 gigabytes to avoid these problems. So see your hard drive manufacturers web site for advice. Or see www.seagate.com for their advice, which is better than other sites.
* Some old IDE interfaces (the male part) had all 40 pins. Newer interfaces and cables have a key pin so that you cannot connect the cable around the wrong way. You may bend over and break off the key pin so that you may use new KEYED cables on the non-keyed interfaces.
Executive summary of SATA.
SATA stands for serial ATA. The SATA cable has a small short 4 wire cable data connector with thin style connection, and a similarly thin style power socket.
There is one cable for one drive. There is no setting for master and slave on the SATA drive.
SATA drives can only work on SATA interfaces. You will need to buy power adaptors to put the SATA drives into cases with no existing SATA power cables.
You can buy adaptors to put IDE/ATA drives onto SATA interfaces. There is no advantage to switching to SATA except where you ran out of the older IDE interfaces in your system. I guess you set the drive to master when you do that.
SATA can run faster than the older 40 pin IDE cable standards because the Serial data line is so much faster. It is a differential * modulation technique , where the signal is in the voltage difference between two conductors. This is immune to COMMON MODE noise - which is important as induced noise on the cables effects both conductors the same and is therefore common mode noise. And that means induced noise does not disturb the demodulation.
(* PATA IDE 40 pin connectors use single ended signalling - one conductor each. Ok the 80 conductor cables use a conductor as shielding, but that doesnt make it differential signalling !)
History of “IDE”
What does “Integrated device electronics” really mean ?
You asked for it.
Before the IDE interface type, IBM PC/XT/AT's (and various other achitecture microcomputers) used ST-506 MFM or RLL interface drives, or ESDI drives. These drives had minimal electronics on the drive. The interface card required a microcontroller and modulator/demodulator chips. These pre-IDE drives required both Data and Control cabling, which connected using edge connectors onto the PCB , like the old style PC floppy drive cable connector.
So the IDE interface device each have their own controller - that means the device has a higher level of Integrated Device Electronics. Because each device looks after modulation , head movement ,etc, for itself, different IDE devices can use different modulation techniques, different types of head movement mechanisms, etc, the interface supported new technology with no problem. That allowed the IDE interface to live from 1986 to 2005 and beyond.