 The magazine of the Melbourne PC User Group Installing a second IDE drive George Skarbek gskarbek@melbpc.org.au |
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The price of hard disks is falling rapidly and many users are adding a second hard disk to their computer rather than replacing the existing one. In this way the second disk acts as a backup and makes the copying of data from the old to new very much easier. Doing it yourself is not difficult. If you succeed you gain experience and the satisfaction of doing the job. If you fail, you take your computer to the dealer, which you would have done if he was doing the job anyway.
Preliminaries
Before buying a disk, make sure that your existing disk is connected to an IDE controller. In most cases it will be. There are several shareware programs on the BBS that will identify the type of hard disk controller in your computer. When purchasing the drive, get the mounting screws. These are generally not supplied - if you forget to get them you will have to take one or two out of the floppy or existing hard disk mounting.
Before starting create a bootable floppy disk by typing FORMAT A: /S and then copy at least FORMAT.* SYS.* FDISK.* SCANDISK.* (or CHKDSK.* if your DOS is prior to 6.2) onto the floppy. Check that you can boot from that floppy and that you can access the hard disk. Do not proceed until this step works.
With both disks installed it is very easy to copy one entire disk to the new one, however as a safety precaution copy your most important documents onto floppies as a backup measure in case something goes disastrously wrong. These files should be just your data files from your word processing, spreadsheet, Quicken, database, drawing or other important application programs. Do not copy the application programs themselves as these can be restored from the original disks. Also copy *.INI *.GRP and *.PIF from the Windows subdirectory.
Physical connections
Often the hardest part of the installation is to open up the computer to get access to the second drive bay. Make sure that both the power cable and the flat data cable coming from the existing disk will reach the new drive. The 40-pin flat cable has a red stripe on one side to indicate pin one. Although it will fit in either way, it will only work when connected correctly. Usually no harm is done by connecting it back-to-front but early Samsumg 120 MB and 170 MB drives can be destroyed by doing this. Pin one is always marked on the drives themselves.
To connect two IDE drives one must be set as a Master and one as Slave. This is done by setting the jumpers correctly on both drives. With only one disk drive connected, no jumper is required. With the new drive, these jumpers will be identified, but in many cases there is no documentation with the old drives. Usually one of the settings has at least the letter M displayed. If nothing works, experiment with all combinations, as there are only a few choices. When starting, do not fully install the new drive into the computer but leave one or both drives sitting on top or beside the computer in case some settings must be altered. Ensure that if the drive is to be resting on a metal surface that a sheet of cardboard is placed under the drive to prevent shorting of the electronics. If you do not have a spare power lead then buy a power splitter which should be available from most computer shops.
Software
After connecting the drives and switching on power, the CMOS setting must be altered to tell the computer about the new drive. You should only enter the Head, Cylinder and Sectors per Track information. Leave the other fields blank. Remember to alter the CMOS configuration with each reboot if you are physically swapping drives.
Having successfully booted, use FDISK to partition your drive. A typical screen is shown in Figure 1. Be very careful as FDISK will totally and irretrievably destroy all data on the hard disk. Be very sure that you are selecting the correct drive.
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To display only the hard disk's partition information, type FDISK /STATUS.
Usually allocate all of the hard disk to DOS, although there are no set rules. The primary partition will become drive C, and additional partitions will become D, E etc. If anyone is still using DOS 3.3 this is a good time to upgrade. DOS 3.3 will support a maximum partition size of 32 MB. This means using the letters C to Z for your drives will only take up to just over 700 MB.
With everything on one drive it is easier to find files, although there are shareware utilities such as Wiz that search across all drives for files. With several logical drives you can segregate programs, such as all kids' work on one logical drive, all games on another etc.
Partitioning will also reduce cluster size. Cluster size is not a hardware limitation, but a feature of the DOS (Disk Operating System). When DOS was designed nearly 20 years ago, only floppy disks and tapes were used in personal computers. The File Allocation Table (FAT) was designed to keep track of where the data is stored. It allowed for 64 K entries, and each allocation unit was 512 bytes. This allowed for hard disks to grow up to 32 MB. In the days of only floppies, 32 MB would have appeared almost astronomical for PCs, especially when the first hard disks were 5 MB, that cost far more than a Pentium computer today with a 1 GB disk.
When DOS 3.0 appeared in 1984 the FAT was altered. It was still limited to 64 K allocation units, but the units were not restricted to 512 bytes. The bigger the disk, the bigger the allocation unit. As an example, with disks between 256 MB and 512 MB the allocation unit is 8,192 bytes. With a 1 GB drive, the allocation unit is 32,768 bytes. It determines the minimum increment of disk space taken up by a file. If you create a file containing one single character, the disk space will drop by 32,768 bytes. If you put 32,000 characters into that file, it will still consume 32,768 bytes. However the first file will have over 99% of slack space, the second one will have very little. However the DIR command reports the file size as one byte for the first file and 32,000 for the second. On average, with each file, you will lose 16 KB. On a 512 MB disk the cluster size is 16 KB and the average loss is 8 KB.
Now for the bad news on partitioned hard disks. If one logical drive fills and the other(s) is largely empty, you cannot resize the partitions without deleting everything on the partitions, unless you have some specialised software. Therefore much thought needs to be put in before starting. The specialised software required to alter disk partitions without losing your data is called Partition Magic, by Powerquest, and it costs about $100. Version 2 works with Windows 95.
Having partitioned the disk, remember to create an active partition, otherwise the computer will not boot. You will be able to boot on a floppy and access both drives without any problems, but some head-scratching will probably result.
To copy software, after both drives are connected, just type XCOPY D:\ C:\ /S /E, assuming that the new drive is C:. This is very much easier than backing up the hard disk, installing DOS and the backup software and then restoring from lots of floppies. The only possible problem is that XCOPY does not copy hidden files. To find all your hidden files on the hard disk type DIR C:\ /S /AH /P. Some knowledge is required if any of these must be copied, but usually none are required. Delete the read-only file in the Windows subdirectory called SPAR.PAR. This contains information about the Windows swap file, which is not copied over but will be correctly recreated by Windows.
When it all works, install the drives into the computer but do not tighten the screws more than a bit more than finger-tight. You are not installing a structural member and the screws have a fine thread and they are only designed to stop the disk from sliding around when the computer is being moved.
Possible problems
Now for some problems that may arise.
If your computer is relatively new, less than about 18 months, you should have no problems and your BIOS and controller can overcome (fool) the DOS limitation of 1024 cylinders being the maximum supported.
There are two solutions for older systems. The first; purchase a new enhanced IDE controller. These are relatively low cost, will allow up to four drives to be connected, boost performance, are not slowed down by the older disk and overcome the 1024 cylinder limit. Another solution is to purchase a disk such as Maxtor that has its own disk manager and will do its own translation. Typically this is less than 10 KB and loads from CONFIG.SYS.
Another problem is the lack of compatibility between different brands of disks in the way Master and Slave are supposed to work. These problems are rare and pertain to old smaller-capacity disks. If there is a conflict, it may mean that the two just cannot coexist together, and there is no fix.
Warning: Never attempt a low level format on these large disks unless you are absolutely certain of what you are doing. Using DOS to format the disk is OK. See Peter Ackroyd's excellent article (tale of woe and lesson) in
PC Update (Dec 95) on problems with LBA (Logical Block Addresses) and low level formatting. Also on the next page Richard John has a more positive article on upgrading the hard disk.
If you have read to here and are a bit overwhelmed, here are the main steps:
- Install the second disk, either as slave or master
- Set the CMOS when booting for the first time
- Partition and format this disk
- Copy or install any software onto it
Reprinted from the March 1996 issue of PC Update, the magazine of Melbourne PC User Group, Australia
