Newsgroup: it.comp.hardware.storage
Titolo: Using two hard disks

Hello,
I can use these 2 hdd both as single-drive-system masters.  When I try
to put one as slave though I get error 1782 (controller test failure)
during bootup.  Here are the relevent specs:
1) Quantum Fireball SE (4.3 GB)
    a) I want this to be the master
    b) Here are the pins:
        |     |     |     |
        |     |     |     |
            pk   cs  ds
DS pins results in a workable single drive master.  CS is for Cable
Select and PK is for Slave.
2) Maxtor (model: 71626AP; 1.6 GB)
    a) I want this to be the slave
    b) Here are the pins:
        |      |      |      |     |
        |      |      |      |     |
       j20  21   22    23  24
The documentation I found states that 21 and 22 are not to be used.  J20
is to configure Slave/Master and J24 is for Cable Select.  Having a
shunt horizontally placed across to top row of 20/21 and a vertically
placed shunt on 24 results in a workable single drive master.  See
attached for more documentation on this hd.
Note: I have a Compaq Presario 9642
Question:  What is Cable Select used for?
Thanks in advance,
Peter Matulis

Cable select is not used in most clone PCs but I did see it used in some
HP systems or Compaq system years ago.
Basically the cable selects which drive is the master and slave by the
physically position on the cable. 
Since you have a Compaq system, it might be set up for cable select.  If
you set it up for a master/slave arrangement, your system should be able
to handle it.  Please note that the IDE cable in your Compaq may be a
cable select version which has a wire cut on it and is not usuable in a
master slave setup.
Here is the definition of Cable Select as taken from "Upgrading and
Repairing PCs" by Scott Mueller, page 702, 5th edition.
"You may see a different arangement of cable connections in some IDE
installations. In some installations, the middle connector is plugged
into the motherboard, and the primary and secondary drives are at
opposite ends of the cable in a Y arrangement. If you see this
arrangement, be careful; in some of these Y-cable installations, the
cable, rather than the jumpers on the drives, actually controls which
drive is primary and which is secondary.
Controlling master/slave selection via the cable rather than jumpers on
the drive is performed via a special signal on the IDE interface called
CSEL (Cable SELect), which is on pin 28 of the interface. If the CSEL
line is connected through from the drive to the IDE interface connector,
the drive automatically is designated as primary. If the CSEL line is
open between the drive and the IDE connector, the drive automatically is
designated as secondary.
In the Y-cable approach, the IDE interface connector is in the middle of
the cable, and a separate length of cable goes to each drive. Study this
type of cable closely. If one of the ends of the Y has line 28 open
(usually a hole in the cable through the wire), only the secondary drive
can be plugged into that connector.  HP Vectra systems use exactly this
type of IDE cable arrangement. This type of setup eliminates the need to
set jumpers on the IDE drives to configure them for primary or secondary
operation, but the setup can be troublesome if you do not know about
it."
Here is a web page that explains it quite well from Micro Firmware
Technical Support: 
http://www.firmware.com/pb4ts/cablesel.htm
And of course the PC Guide has info on cable select too.
http://www.pcguide.com/ref/hdd/if/ide/conf.htm
 
Apparently it is part of the ATA-2 and ATA-3 specs and part of PnP
technology. But it didn't get seem to get popular. Apparently you hard
disk controller has to support CS also and of course any other
peripherals you connect to it (CD-ROM, ZIP drive).
Now there have been a couple of ads on web pages promoting cable select
as an option for setting up hard disks and that it is a better way of
doing it compared to the usual Master/Slave method. GSI is offering this
cable and here is info from their Web site. It seems to contradict the
reference from Scott Mueler's book above as far as where the drives fit
on the cable. It seems to be a special adaptation of the Cable Select to
overcome design limitations in the original specs.
http://www.gsi-inc.com/products/csel.html
http://www.gsi-inc.com/products/gsicsel.html
Does it need special hardware like a new controller? I think it is
included in hard disk controllers now and maybe even for a while. GSI
offers a controller with EIDE and Cable Select abilities.
Personally I will stick to master/slave jumpers as it is not difficult
to set them and there are sites online to get jumper settings for almost
all old and new hard drives. Plus how often does one need to change them
once set? 
The advantage to cable select is that you would not need to know the
jumper setting for master or slave.  You just put it on the cable in a
physical position, just like on a floppy cable (A drive always on the
end). Great potential. And it would make it extremely easy to add a hard
disk. There is no performance gain. The disadvantage is that it would 
confuse a lot of people out there for quite a while if this were to 
change and become standard.
But I have no practical experience in setting CSEL up, never tried it. I
just came across it in a question in a post one day and looked it up in
my reference books and have been gathering info on it since.

---------
Please remove the XYZ in the e-mail address if replying

, 
smat...@total.net
 says...



To reply by email, remove the *NO_SPAM* from my email address.