Computer Archtecture
A+ Guide to Manageing and Mainting Your PCs
Chapter 8 Understanding and Installing Hard Drives.

I. Hard Drive Technology
   A. Tyoes of Hard Drive Intefaces
      1. EIDE Standards
         i. First one was ATA-3
            a. allows up to 4 drives on a machine
            b. all drives must follow the ATAPI interface standards
         ii. There are several different standards
            a. Each one improes on previous
            b. There is some overlapping
            c. Special cable (80 conductor) is needed for more recent ones (over ATA/100)
         iii. Newer standards support the much larger drive capacity
         iv. There are special adapters for the larger cables if the connection on the mother baord will not support it.
         v. The can be two drives on the primary cable (master and slave) and two drives on the secondary cable (same)
      2. Other interface Standards
         i. SCSI - not discussed here
         ii. IEEE 1394 - FireWire - USB has been supported instead of firewire
         iii. Fibre Chanel - High end systems
   B. How Hard Drives Work
      1. one or more platters that spin in unison
      2. Each surface is called a head (not to be confused with a read write head)
         i. Each head has tracks and sectors
         ii. If you take a specific track and sector and go through all the heads that is called a cylinder
         iii. The whole cylinder will need to be filled before it will move on to the next one.
         iv. Hard Drives require controller boards to interpert what is going on
            a. Older systems had a card that went into IO slot as well as on the drive
            b. newer ones are just on drive
   C. IDE Technology
      1. Tracks and sectors on an IDE Drive
         i. Older drives had a fixed sectoring that broke the drive up into slices. this kept the sectors constant
         ii. New drives use zone bit recording that allow for more sectors to be in outer drive ring than in inner one.
      2. Low Level Formatting
         i. Older drives with fixed sectors would often have programs in the bios to refesh the formats on them
         ii. Newer drives have this done at factory
            a. Program may be available at the manufacture's web site to fix them should they get bad.
            b. most people just toss them away
II Communicating With the Hard Drive BIOS
   A. Calculatin Drive Capicity on Older Drives
      1. Older drives: multiply heads * cylindars * sectors per track * 512 bytes per sector and that would give you disk storage.
      2. Newer drives need to fake the system out with the help of the BIOS
   B. Adjusting for More Complex hard drive organization
      1. CHS mode - Drive tells BIOS that it has a certain combination of heads/cylindars/sectors (max size 528MB)
      2. Large Mode - ECHS mode - sends geometry to BIOS which sends different information to the OS (max size 8.4 GB)
      3. LBA mode (large than 504 MB)Sends information to OS, BIOS sees sectors as long list of numbers
      4. OS bypassses the BIOS altogether. (windows NT/2000/XP)
   C. Installations Using Legacy BIOS
      1. Newer drive older system
         1. Let BIOS see it as smaller drive
         2. Upgrade the BIOS
         3. Upgrade the Mother Board
         4. Use software to act as go-between the BIOS and the OS
         5. Use an adapter card to substitute for your BIOS
III How a Hard Drive is Logically Organized to Hold Data
   A. If using Windows you must decide
      1. Fat/16 -works with DOS and Windows95 (and all newer versions)
      2. Fat 32 - works Windows 95 with patch, and all newer versions
      3. NTFS - Works with Windows NT, Windows 2000, Windows XP
      4. Your choice will be limited to what operating system you have and if multiple OS's installed, which ones will need to read which drives
      5. Generaly the larger the drive, you should take the newer technology so that slack size is minimized.
   B. Steps after drive instaled
      1. Low level format - creates tracks and sectors - not done with newer drives
      2. Partiton - sets the drive up into one large drive or several virtual smaller ones. Use FDISK in dos/windows (diskpart in XP)
      3. High level format - Use Format command in dos/windows - creates the information needed for OS to keep track of things
   C. Hard Drive Partions and logical Drives
      1. If you choose to break you drive up into multiple virtual drives, even if you ceate three or more you will really only create two
         i. Primary partion (the one that boots usualy)
         ii. Extended partion (holds 1 or more logical drives)
      2. The Master Boot Record (MBR) is 512 bytes, and is accessed during POST to see where OS is.
      3. Active partion is always the first partion on a drive (2000/xp call it system partion)
      4. DOS/Windows 9X allow 2 partions
      5. NT/2000/XP can have 4 partions
         i. Partion can be primary (having one logical drive)
         ii. Partition can be extended (more than one logical drive), but only one of these can be on drive.
      6. Active partition is always a Primary partition.
   D. Choice of File Systems
      1. Fat 16
         i. uses 16 bits for sector cluster entry in fat
         ii. limits the amount of clusters that can be on hard drive and hence, cluster size is larger
         iii. in larger drives can create a lot of slack space when small file in size is save to a large cluster size
      2. Virtual File Allocation (VFAT)
         i. Windows 95 and Windows for Workgroups (3.11)
         ii. supports larger file names
         iii made obsolete by fat 32
      3. FAT 32
         i. WIN 95 OSR and above
         ii 32 bits for FAT entry
         iii more clusters relates to smaller cluster size, less slack space.
      4. NTFS
         i. Does not use FAT system at all
         ii. uses a database called master File Table (MFT)
         iii. Writes the information on the middle of the drive rather than the end of it.
         iv. Use on systems that will not have multiple OSs on them that are of Windows 9x nature
   E. How many logical drives
      1. Some people put OS on one drive, programs on another and data on third, (or some combination)
      2. In reality you want to have the fewest drives with the cluster size to a minimum.
      3. If you have two hard drives and each has a primary partiton and extended partions, the primary partions will take the first drive letters and the extended will take the others. This can be changed by not putting a primary partiton on the second drive.
   F. When to partion a drive.
      1. First install
      2. Giving errors, in an effort to save the drive
      3. Suspect a virus (back up important information first)
      4. Wipe clean to install a new OS
      5. FDISK is used to do it, but not user friendly, some third party software (partion Magic is one) is a bit more friendly
      6. Be careful of software used to trick out BIOS
   G. What Happens During Formatting
      1. The OS Boot record is created
      2. The FAT is ceated
      3. The Root directory is built
IV. Installing A Hard Drive
   A. Prepare for installation
      1. Jumper settings
      2. Change CMOS if needed
      3. Use FDISK to create partitions
      4. FORMAT command to format drive
      5. Install OS and other software
      6. Keep notes of everything (CMOS especially)
      7. Make sure you have bootable rescue disk
   B. Read the Documentation (nuff said)
   C. Plan the Drive Configuration
      1. Put faster drives on one channel and slower ones (CD/Zip drives) on the other
      2. Visualize the instalation and plan for what can go wrong
   D. Prepare your work area and take precautions
      1. Proper grounding (straps etc.)
      2. Make suer cables will reach
   E. Set Jumpers and DIP switches.
      1. Most hard drives have setting printed on them
      2. write the original ones down if you are changing them (especially on ones in the machine already)
   F. Mount the Drive in the Bay (and recable it)
   G. If the bay is too large - buy a kit to adapt it.
   H. Use CMOS to Change Hard Drive Settings (view what changes if any made)
   I. Setup for Large-Capicity Drives
      1. Set Ultra DMA, PIO, and DMA modes to AUTO
      2. Some BIOS will let you set to boot from SCSI drives even if IDE drive is present.
      3. Make sure you set it to boot from device you want (Floppy, CD, IDE, ZIP)
   J. Use FDISK to Partion a Drive
   K. Format Each Logical Drive (FORMAT C: /s [/s is for system files if you wish to make it bootable] )
   L. Using Windows to Partiton and Format a New Drive
      1. If new Windows and new HD install boot from CD to install (change BIOS first)
      2. If 2nd drive being istalled, and Windows 2000/XP is on first drive, you can use Disk Management to partiton and format drive.
V. Troubleshooting Hard Drive Installations
   A. If installing mixed drive types (IDE and SCSI or IDE and IDE on controller) stop and get help till you are more expereinced
   B. Make sure that you did not introduce other problems when you replaced covers/put drive in slot etc. Look for cables disconnected or memory bumped.
   C. If Drive not present recheck you set AUTODETECT in BIOS
   D. Did you FORMAT C: /s?
   E. Check the web site of drive manufacturer for suggestions.

[Listening to: Here to Eternity - For This Cause - For This Cause (03:47)]