Week 8 Lesson Plan Addendum

Hard Drive Introduction

Hard Disks are laid out in a somewhat similar fashion to the geometry of the floppy drive. As you remember, the addressing for the floppy drive is known as FAT12. The addressing for the first hard disk drives was FAT16 but more recently has gone to FAT32. The next  regimen of disk layout changed the addressing so that it is no longer based on a FAT table and its limitations. It is based on NTFS (New technology File System) and is more secure and subject to less failures. The primary difference between the FAT based drives and the NTFS is the location of the FAT MBR and boot sectors of the disk. On the NTFS system, the information is loaded onto the last sector of the disk instead of the first sector. Remember that the first sector is exposed to more ESD and handling damage so by placing the boot files at the end of the dosk (near the spindle) it offers more protection from ESD and handling issues.

Maximum size of drive- the maximum size of disk drives is determined by the number of address bits it can support. A Fat 16 system had only 32 wires running to the disk drive whereas the 64 bit system has 64 wires. As you remember from math, the number of wires determines the maximum number of the highest address (if all wires are turned on representing all ones). Mathmatically we can determine the address by using 2 to the Nth power where N=# of wires. We must then multiply this result by 512 bytes per sector to determine the maximum size of a disk drive. (one sector per address location)

Note: above 137GB, a special IDE cable must be used that contains an additional 40 wires to offer shielding protection for the transfer of data. At that point, 137GB, noise in the system starts to denigrade the passage of data. The additional wires shield the disk data from degredation by grounding out excess noise and EMF.

Installation of a Hard Drive

Set jumpers or DIP switches; physically install drive; attach power cord and data cable

Inform CMOS of new drive

If installing an OS on the drive, boot from OS setup CD (and skip next two steps)

If drive is not intended to hold an OS, use Fdisk or Disk Management to create partition(s) and divide extended partition into logical drives

For second drive, use Format command or Disk Management to high-level format each logical drive

Steps for preparing a hard drive to hold files

Low-level format (usually done at the factory)

Partitioning the hard drive

High-level format

After using Fdisk, you must reboot the PC before you format the drive

Commands used to format logical drives C, D, and E:

Format C:/S

Format D:

Format E:

Maintenance and care - as with floopy drives, hard drives must be maintained for optimal performance. There are several software tools used regularly. Scandisk, chkdsk, and format are very useful and prolong the life of disk drives.  We will establish monthly maintenance cycles and develop preventative and backup schedules in our lesson about proper troublshooting tips and then again when we make our performance notebooks.

LAB - At this time, lets install and test the drives we have in the lab area. Very few of these drives work well so we will optimize them after installation. Do lab installs and begin troublshooting.