| Introduction to hard drives |
| Identify various types of hard drives and understand technology and advantages of each | |
| Describe how data is stored on a hard drive | |
| Manage a hard drive to by using DOS and Windows commands | |
| Optimize hard drive performance by using the System Tools utilities |
| Methods used to adjust for smaller tracks closer to center of platter | ||
| Write precompensation | ||
| Reduced write current | ||
Integrated Device Electronics (IDE) technology
| A hard drive whose disk controller is integrated into the drive | ||
| Eliminates need for controller cable | ||
| Increases speed | ||
| Reduces price | ||
| Most system boards provide one or two IDE connections directly on system board | ||
Hardware subsystem with an IDE hard drive
Tracks and sectors on MFM and RLL technologies
| Use either 17 or 26 sectors per track | ||
| Wastes drive space | ||
| Number of bytes a track can hold is determined by centermost track | ||
Tracks and sectors on an IDE drive
| Use zone bit recording | ||
| Tracks near center have smallest number of sectors per track | ||
| Number of sectors increases as tracks get larger | ||
| Have 512 bytes per sector for every sector on the drive | ||
SCSI (Small Computer Systems Interface) technology
| Provides a standard for communication between a subsystem of peripheral devices and the system bus | |
| Most SCSI drives are IDE drives |
| General categories | ||
| Narrow (8 bits) | ||
| Wide (16 bits) | ||
| Ways a SCSI cable can be built | ||
| Single-ended | ||
| Differential | ||
| Three major standards | ||
| SCSI-1 (Regular SCSI) | ||
| SCSI-2 (Fast SCSI) | ||
| SCSI-3 (Ultra SCSI) | ||
Summary of different SCSI standards
Sample configuration of a SCSI subsystem
Other variations of SCSI hardware and software
| Termination | ||
| Several ways to terminate power | ||
| Types of terminators: passive, active, forced perfect | ||
| Device drivers | ||
| Advanced SCSI Programming Interface (ASPI) | ||
| Common Access Method (CAM) | ||
| Host adapter issues | ||
| Compare installation procedures and options | ||
How a hard drive is logically organized to hold data
| Steps in preparing a hard drive to hold data | ||
| Low-level format | ||
| Partitioning the hard drive | ||
| High-level format | ||
| A portion or all of a hard drive partition that is treated by the operating system as though it were a physical drive containing: | ||
| Boot record | ||
| FAT | ||
| Root directory | ||
The FAT and the Root directory
| The OS uses the FAT and a directory to keep track of which clusters are being used for a particular file, together with other information about the file | |
| To the OS, each logical drive is treated like a single floppy disk: a physical drive divided into three logical drives is equivalent to three separate physical drives |
The FAT and the Root directory
The FAT and the Root directory
The FAT and the Root directory
| Virtual file allocation (VFAT) | ||
| An improved method of hard drive access that allows for long filenames and 32-bit access | ||
| FAT32 | ||
| Allows better management of very large hard drives | ||
| The root directory | ||
| Layout is the same as for floppy disks | ||
Operating System commands to manage a hard drive
| DOS commands | |
| Windows 3.x | |
| Windows 9x |
DOS commands to manage a hard drive
| MKDIR or MD | ||
| Creates a subdirectory entry in a directory | ||
| CHDIR or CD | ||
| Changes the current default directory | ||
| RMDIR or RD | ||
| Removes a directory | ||
DOS commands to manage a hard drive
| TREE | ||
| Displays directory structure of a hard drive or disk | ||
| ATTRIB | ||
| Displays or changes the read-only, archive, system, and hidden attributes assigned to a file | ||
DOS commands to manage a hard drive
| PATH | ||
| Lists where DOS and Windows 3.x should look to find executable program files | ||
| Batch files | ||
| Series of DOS commands that will execute | ||
Using Windows 3.x to manage a hard drive
| Primary tool: File Manager | ||
| Create directory | ||
| Delete a directory | ||
| File properties | ||
| Batch files | ||
Creating a directory in Windows 3x
Creating a directory in Windows 3x
Deleting a directory in Windows 3x
Using Windows 9x to manage a hard drive
| Primary tool: Windows 9x Explorer | ||
| Create a new folder | ||
| Delete a folder | ||
| File properties | ||
Creating a new folder in Windows 9x
Creating a new folder in Windows 9x
Deleting a folder in
Windows 9x
| Fragmentation | |
| Cross-linked and lost clusters | |
| Disk compression | |
| Disk caching |
| Distribution of data files in noncontiguous clusters; increases data access time | |||
| Routine maintenance: defragment the hard drive | |||
| DOS | |||
| DOS 6+ DEFRAG or a utility software package | |||
| Windows 98 | |||
| Defragmenter utility | |||
Windows 98 Defragmenter utility
Cross-linked and lost clusters
| Cross-linked | ||
| More than one file points to them | ||
| Lost | ||
| No file in the FAT points to them | ||
| To repair: use ScanDisk utility in either DOS or Windows 9x | ||
Cross-linked and lost clusters
| Compresses data on a hard drive to allow more data to be written to the drive | ||
| Works by | ||
| Storing data on the hard drive in one big file and managing the writing of data and programs to that file | ||
| Rewriting data in files in a mathematically coded format that uses less space | ||
| Host drive | |
| Compressed volume file (CVF) |
Disk compression in
Windows 9x
| Uses DriveSpace to: | ||
| Assign different drive letter to hard drive, (e.g., H) | ||
| Compress entire contents of hard drive into a single file on drive H | ||
| Set up the drive so that Windows 9x and other applications view this compressed file as drive C | ||
| Configure Windows 9x so that each time it boots, DriveSpace driver will load and manage the compressed drive | ||
| A method whereby recently retrieved data and adjacent data are read into memory in advance, anticipating the next CPU request | ||
| Two kinds of hard drive caches | ||
| Hardware cache | ||
| Software cache | ||
| Disk cache in DOS and Windows 3.x | ||
| SMARTDrive | ||
| Other packages (e.g., Norton Cache, Mace Cache, Super PC-Kwik Cache) | ||
| VCACHE in Windows 9x | ||
| DOS buffers | ||
| An area in memory where data waiting to be read or written is temporarily stored | ||
DOS commands to avoid with Windows 9x
| Don’t use disk utility software that does not know about VFAT, long filenames or FAT32 | |
| Don’t use FDISK, FORMAT C:, SYS C:, or CHKDSK while in a DOS session | |
| Don’t optimize or defragment the hard drive using software that does not know about long filenames |
DOS commands to avoid with Windows 9x
| Don’t run hard drive cache programs unless written especially for Windows 95 or Windows 98 | |
| Don’t use older DOS backup programs (BACKYUP, MSBACKUP) |
| Compared hard drive technologies | ||
| IDE | ||
| SCSI | ||
| Partitioned a hard drive | ||
| Identified OS commands for managing hard drives | ||
| Discussed optimizing hard drives | ||