Can someone explain Master and Slave?

[Felecha]

I just gotta learn more some time. I know enough about computers to not be afraid to go in and install a device, but not enough to build one.

Something I've heard about since day one, of course, is the terms master and slave. I just never have understood what they mean, except that I sort of expect that one is in control and the other isn't.

I have a custom box built 4 years ago at a computer store, ABIT KT7 RAID with 2 IBM Deskstar 75GXP 30GB hard drives, a CD, and a CDRW. Athlon 900 TBIRD, 768 RAM, runs Win2K. This week I bought a DVDRW and have installed it to replace the CDRW, and was thinking, now is the time to learn more.

When it was built, only one hard drive came in, the other got back ordered, so I took delivery and when the second came I installed it myself and mixed up something and got help on the phone from a friend. When I finally got the right thing in the right hole, or so it seemed since it did boot and everything ran, it never did show everything in the BIOS screen (Award Modular BIOS v6.00PG). When I boot I see the first screen

Primary Master IBM DTLA
Primary Slave Pioneer DVDRW
Secondary Master CRD-85208
Secondary Slave None

Then a screen starting with "Highpoint Technologies" that says "Scan Devices"

Primary Master IBM DTLA
Primary Slave None
Secondary Master None
Secondary Slave None

I'm puzzled by all the None's. I'm not aware of anything not working right.

*** Later - I figured I should look. I can barely see in there, but I see 5 slots. One is smaller, and it has the floppy. There are 2 white slots, IDE 1 and 2, and 2 orange slots IDE 3 and 4

IDE 1 Cable goes to one of the IBM's, then on to the new DVD
IDE 2 Just the old CD
IDE 3 Just the other IBM
IDE 4 empty

OK, that must have something to do with the first BIOS designations. But the second screen?

And, is there anything wrong with it as it is? Again, it was 4 years ago and I've forgotten the details. I can't be sure of how the guy who built it did it before I did whatever I did when I added the second IBM. He was very sharp, I can't believe he wouldn't know how to do it right.

Thanks!

Also, maybe there's a recommended tutorial out there?

 

[imported_Phil]

You've plugged the new hard disk into the Highpoint RAID controller, which gives you an additional four devices. It's fine, don't worry about it

Windows will still pick the drive up if you've installed the drivers.

Oh, and Master = primary device. Slave = secondary device. That's it.

 

[Felecha]

so what then is the "meaning" of primary and "secondary"? Does one get precedence? Yesterday at work I plugged something in that needed a jumper setting to Master and I did what I was told but didn''t know what I was doing (the guy was out the door, and it worked, and I havent seen him to ask for an explanation)

 

[imported_Phil]

Originally posted by: Felecha
so what then is the "meaning" of primary and "secondary"? Does one get precedence? Yesterday at work I plugged something in that needed a jumper setting to Master and I did what I was told but didn''t know what I was doing (the guy was out the door, and it worked, and I havent seen him to ask for an explanation)

No, not at all. It simply differentiates between the two drives- you need some way of saying "that's the first one, and that's the second one". Of course, this has all been done away with after the advent of SATA.

 

[leigh6]

Primary and slave really do not mean much. In order to have more than one hard drive or optical drive (cd/rom, dvd/rom, etc.) You need to designate one as the primary. The rest just become "slaves" (Think of this as just an added drive, so added drives all become slaves). They are just terms. If you had 2 "primary's" one of them will just not work. You change the jumpers on the drive in order for the system to recognize the extra drive(s) as a "slave"

 

[MobiusPizza]

I am the master, you are the slave
*Evil laughs*

j/k. I have no idea why such a stupid design was implemented in the ATA specification. The terms serve no purpose other than for the controller to "distinguish" the drive; since an PATA IDE channel has 2 ports.

 

[Felecha]

OK, so the only problem would be setting more than one to Master on the same ... channel? You use the term channel, is that what I called the "slot" that the end of the cable plugs into on the board?

So there's no problem with the configuration I described? No advantage to putting each drive alone on a channel? Nothing to worry about on the BIOS screens?

 

[JonnyBlaze]

Originally posted by: Felecha
OK, so the only problem would be setting more than one to Master on the same ... channel? You use the term channel, is that what I called the "slot" that the end of the cable plugs into on the board?

So there's no problem with the configuration I described? No advantage to putting each drive alone on a channel? Nothing to worry about on the BIOS screens?

there is an advantage to having drives on seperate channels. only one drive on a channel can be accesed at a time.

 

[SVT Cobra]

Originally posted by: JonnyBlaze

Originally posted by: Felecha
OK, so the only problem would be setting more than one to Master on the same ... channel? You use the term channel, is that what I called the "slot" that the end of the cable plugs into on the board?

So there's no problem with the configuration I described? No advantage to putting each drive alone on a channel? Nothing to worry about on the BIOS screens?

there is an advantage to having drives on seperate channels. only one drive on a channel can be accesed at a time.

yes if you can i would out a seperate drive on each channel

 

[Felecha]

OK, will do. I presume it's a straightforward thing

No - I would have to get a cable, wouldn't I? I have 2 old retired computers that my daughters had LONG ago but the cables are the same ribbon type. They should work?

 

[CrispyFried]

If they are old they are probably 40 conductor, you need the newer 80 conductor cables for UDMA speeds. The plugs are the same though, do a side by side comparison amd youll see the difference in the wire count.

 

[Felecha]

thanks

 

[imported_FishTaco]

You'll also run into the term cable select (CS), this just means master and slave is determined by what plug is connected to the drive.

 

[P0ldy]

All you wanted to know and more.