SOS Pages

These are some quick instructions on how to get a new IDE hard drive into a PC and get it to work.

General PC Hard Drive info

There's alot to know about PC hard drives. A good starting point for learning more are the various hard drive vendor's web pages. Seagate has a good FAQ and install docs with good info, as does Quantum. There is also an EIDE FAQ, a list of hard drive lingo, and diagnostic tools. It's worth you while to browse through these sites. In the rest of this page I'll assume you're familiar with the basic terms introduced there. Also, we'll ignore the question of SCSI drives. Almost all PC's (running Win3.x or Win95) on campus (currently) use EIDE hard drives and controllers.

Settin' it up

Before you start rippin' things open there are several pieces of info you'll need to know. You'll need to know all the drive parameters (Cylinders, heads, sectors etc...) for all the drives that will be going in the computer. If there's a drive already in the machine that will be staying in you can often get the info right out of the system BIOS. (which you can get into by hitting F1 right after the memory check at boot on most machines). Most newer drives (from friendlier manufacturers) have the necessary parameters written on the outside of the drive. It's a good idea to write all these down on a separate sheet of paper since it may be hard to read them when the drive is installed. If neither of these does the trick you can try the manufacturer's web site, or the web site of a hard drive dealer. If you know the exact model number (which should be indicated somewhere on the hard drive) you should be able to find out necessary parameters.

Next you'll want to figure out whether the drive will be a master or slave, and which IDE chain it will go on. While most older PC's have only 1 IDE chain (a single plug on the motherboard to which you attach a cable with two other plugs allowing a maximum of 2 IDE devices (either CD-ROM's or hard drives)), many of the newer machines (Pentia and above) have 2 IDE ports on the motherboard. The normal arrangement is to have the hard drive as a master and the CD-ROM as slave (if you've only got one chain to work with). Or to have a hard drive alone on one chain (along with any other hard drives), and the CD-ROM on the other chain. (this is preferable for performance reasons if you've got two chains). Note that it is possible to add additional IDE chains via plug-in cards. (Many Sound Blaster cards come with an extra IDE connector--Gateway removes the pins from this connector on the Sound Blaster cards it ships to avoid conflicts). Don't try to add a 3rd IDE chain if the computer already has two. Once you've figured out which chain the device is going on (you may have to look at the BIOS/manual/motherboard to figure out how many there are and what's currently connected to 'em), you then need to figure out who's master and who's slave. (no jokes please). If there are two devices on an IDE chain one needs to be master and the other slave. This can be set using jumpers on the drive. The details of where the jumpers are, and what the different configurations are fall in the same category as the parameter info--look on the drive, in the manual, on the manufacturer web page....

Finally a comment about EIDE and LBA. Until recently IDE hard drives couldn't be larger than 528 megs. The IDE standard simply didn't allow it. Then the Enhanced IDE standard (EIDE) was created which allows "large block addressing" (LBA). This allow IDE drives to be (much) larger than half a gig--up to 8.4 GB with standard 28-bit LBA. Unhappily for this to work well both the hard drive, and the hard drive controller (which is built into the motherboard for most computers we deal with) have to be aware of this fact. Most of the 486's on campus don't have EIDE controllers with LBA support on their motherboards. That means they can't deal with hard drives larger than 528 megs. There are several solutions to this dilemma. There are software kludges that work to varying degrees that the drive manufacturer's send out. Essentially you run the software off floppy (following the instructions carefully) and when you're done the computer can deal correctly with the larger hard drive (although the BIOS setting won't correctly reflect what's going on). Another solution is to put the "wrong" settings into the BIOS for the drive parameters and have the computer treat the large hard drive as a smaller one. Tricking the computer is often a risky thing so I won't give any details on this (plus, I don't remember the necessary settings myself). Another solution is to use a plug-in card with an EIDE controller. Again follow the manufacturer's instructions and keep your fingers crossed.

Another advantage of EIDE is the integrated ATAPI (AT Attachment Packet Interface) standard--this allows devices such as CD-ROMs and tape drives to be detected automatically. Perhaps not by coincidence it frequently allows EIDE hard drives to be automatically detected as well, thereby transforming a nightmare of cylinder and head information into a relatively easy task--slap the drive in, turn on the computer, and start shunting stuff onto the drive. Much easier.

Putting it in

The next step is to open up the computer and put the drive in place. As always you want to make sure the computer is turned-off and unplugging it couldn't hurt. (You don't want to accidentally bump the power button and turn things on when you're mucking about inside.) Also make sure you keep yourself grounded either with a grounding strap, or by regularly making good, firm, friendly contact between your skin and a non-sensitive, metal part of the case (the power supply is a good choice). Most PC cases these days have several drives bays in which you can slide a standard 3.5" hard drive. Then just fix it in place with screws through the case into the pre-drilled slots on the hard drive. You'll then need to hook up a power cable. There should be a number of identical power cables floating about the inside of the case. They originate in the power supply and and terminate with a chunky d-shaped connector which fits four big pins on the back of the drive. Often it takes a bit of wiggling and force to get these connectors in (and out). Just be sure you've got it oriented the right way. (they don't fit upside-down) Then you'll want to connect a data cable. These are wide, flat ribbon cables that originate on a connector on the motherboard (or IDE controller card). These connectors (depending on design on both ends) may fit into the back of the drive upside-down or right side up. Only one of these orientations will work (the "right" one) Often the IDE cable has one side marked with a subtle red stripe to indicate the side that goes to pin one. Some trial and error may be involved. If there are two devices hooked up to the same IDE chain they'll be hooked to the same cable (which has two connectors).

Once everything is plugged in you'll want to fire it up and make sure it works. You probably want to test things out BEFORE you put everything back together and put the case back on. If some jumper has been mis-set you don't want to have to turn right around and open things up again. Leave the case off until you're sure there isn't anything inside that might need to be tweaked.

Note that if any of the connectors are backwards, power cords are loose, or jumpers are mis-set you can get some really wacky behavior. If the system really freaks out, don't worry, just recheck the connections.

Setting up the soft (and firm)-ware.

If everything went fine in the last step there's still some things you'll need to do before you have a functioning hard drive. First you may need to configure the BIOS. In the very much older computers you'll need to enter the BIOS at boot (you may have to hit F1, or the machine (realizing the presence of the new hard drive) may force you into the BIOS), navigate through the BIOS (usually there's on-screen instructions for this) and enter the hard drive parameters you dug up back before you put the drive in. Often the drives will be listed as Drive c, d, e,f or some such indicating the master and slave drives on the primary and secondary IDE connectors respectively. New BIOSes may "auto-detect" the new drive and with any luck will spit out some info about the new drive as the machine boots.

If for some reason the computer can't connect properly to the hard drive you'll often get an error at boot about the BIOS being mis-configured. Check your connections, and the settings in the BIOS.

At this point with any luck the computer now recognizes the new hard drive at a low-level. (If you're using a program to get around LBA limitations that may need to be installed before this is true). The next step is to get the operating system to recognize the drive. Essentially you need to partition the hard drive for DOS/Win95. (IDE drives are pre-formatted at the factory) To do this you'll need to be able to run DOS either by having the computer boot off a different internal drive, or a bootable floppy. (Note that some BIOS's have a setting which controls which devices can be booted from). Once booted you'll want to run the program fdisk, which allows you to create various sorts of partitions and make them bootable. When you run fdisk on a new drive you'll need to create a new primary partition using option 1, and then use option 4 to make sure you got what you expected. The only real twist to using this program is that the standard DOS file system doesn't allow partitions larger than 2gigabytes. If the drive is larger than that you'll have to create multiple partitions. (they'll show up as additional drives--c:, d:, e: etc....) The OSR2 release of Win95 allows partitions larger than 2 gigs but in doing so fundamentally change the file system so that some older utilities don't work. (the earlier Norton Utilities for Win95 e.g.). The new file system (called "fat32") should probably be all right to install, but if in doubt ask "someone who knows".

If that all goes smoothly you should be home free, and ready to start filling the drive with an operating system, or whatever suites your fancy. Note that Win95 should auto detect the new drive and install drivers for it but hopefully that will go smoothly and automatically. More on that when we know more.

Some possible burps and hiccups. Some of the new Gateway Pentia and Pentia-Pro machines which should auto detect and configure IDE devices sometimes get confused (especially with their CD-ROM drives). The trick here is to reset the "NVRAM" (which stores some plug and play configuration info). For more details see the Win95 setup page. Note that there is now a utility which can reset the NVRAM via software instead of having to open up the case and move the jumper around.