1. Storage Devices Chapters 9 & 10 Ch 9 and 101

2. Magnetic Storage Device Uses magnetism to store data Electricity flowing through a conductor creates a magnetic field. Moving a magnetic field near a conductor creates electricity. A digital signal is created by the rising and falling voltage level (north / south pole) – Raising or Falling is a “1” – No change is “0” Ch 9 and 102

3. Magnetic Storage Device How it works A fine layer of iron oxide coating – Thin plastic TAPE – Thin plastic DISC – Glass, aluminum, ceramic DISC Conductor wound around a read/write head Read / write head floats just.001 micron above spinning disc platter – 5400 rpm (existing stock, slow-high storage) – 7200 rpm (good performance) – 10000 rpm (high performance-reduced storage) – 15000 rpm (highest performance-reduced storage) Ch 9 and 103

4. Magnetic Storage Device Floppy Disc a soft magnetic disc used to store small to moderate amounts of information – 8” stored in paper jacket when not used (360 KB) – 5-1/4” package in hard paper or plastic jacket (360 KB - 720 KB) – 3-1/2 durable plastic case (720 KB -2.88 MB) Floppy disc drive (floppy drive) – Used to read/write floppy disc – Only found on legacy machines / obsolete Ch 9 and 104

5. Magnetic Storage Device Ch 9 and 105

6. Magnetic Storage Device Tape Drives Earliest removable storage device Hold tremendous amounts of data Still used as backup (but declining fast) Major disadvantage data must be read sequentially Being replaced by CD-RW, DVD, Flash Ch 9 and 106

7. Magnetic Storage Device Ch 9 and 107

8. Magnetic Storage Device Hard Drives essentially as stack of non- removable “hard” discs where the iron oxide coating is placed an a hard disc of glass, ceramic or aluminum. Unlike floppy drives hard disc drives have multiple R/W heads Ch 9 and 108

9. Disc Geometry Disc Geometry the surface of a floppy and hard disc is divided into sectors, clusters and tracks. Hard Drives have stacks of discs and are also divided into cylinders Tracks are a set of concentric circles where data is stored Tracks are subdivided into sections called sectors – Smallest sector is 512 bytes Clusters are groups of sectors Ch 9 and 109

10. Disc Geometry Ch 9 and 1010

11. Disc Geometry When writing to a disk heads write to first available sector – Head 1 writes to first avail sector on top of disc 1 – Head 2 writes to first avail sector on bottom of disc 1 – Head 3 writes to first avail sector on top of disc 2… GUID Partition Table (GPT) and Master Boot Record (MRB) contain – MRB (when present)is located as a hidden protected area on the first sector of the hard drive – Boot data – Disc partition Information # of sectors per cluster, clusters per tracks, # tracks, # of read write heads, and etc. Ch 9 and 1011

12. Disc Geometry Ch 9 and 1012

13. Disc Geometry Creating Disc Geometry Low-Level Format: process that determines the type of encoding to be done on the disk platter and the sequence in which the r/w/ head will access stored data Interleave factor describes the way the sectors are laid out on the disc surface Multiple Zone Recording (MRZ) also called zone bit recording sectors are all same size more on outer track than on inner tracks Ch 9 and 1013

14. Disc Geometry Old styleNew style (MZR) Ch 9 and 1014

15. Disc Partition Systems When a disc is partitioned it is divided into separate storage area called logical drives not a separate physical drive but logical drives appear to users as separate drives (i.e. C: D: ect.) Partitions are set up for security, to allow smaller clusters, improved storage efficiency, faster data retrieval Active Partition is the partition from which the operating system will boot. Ch 9 and 1015

16. Disc Partition Systems MBR Partition (master boot registry) all hard drives must have at least one primary partition to contain operating system, boot, and data files – FAT 16 or FAT 32 (File Allocation Table) contain information about where each file starts on the disc FAT 16 - 4 GB max drive / 64 kB clusters FAT 32 – 32 GB max drive / 16 kB clusters – NTFS uses Master File Table to do what FAT does NTFS – 2 TB max drive / 4 kB clusters – Crash Dump status is a location where the operating system attempts to write information when a system failure occurs Ch 9 and 1016

17. Disc Partition Systems GPT (Globally Unique identifier Partition Table) or GUID Partition Table Doesn’t have limitations of MBR based partitions Can handle large Hard drives up to 18 Exabyte (EB) (Exabyte is approximately equal to one million terabytes) (ESP) EFI System Partition EFI = Extensible Firmware Interface – Requires GUID Partition Table Ch 9 and 1017

18. Disc Partition Systems (MSR) Microsoft Reserved Partition Proprietary Recovery Partition also known as OEM partition – contains recovery tools, a copy of the operating system and any other files the manufacturer deems important UEFI Specification Partition Terminology developed as a guide for standardizing the way the partitions are arranged – Protective MBR established and is used to protect GPT when legacy software is used – Protective MBR located first on hard drive followed by GPT Ch 9 and 1018

19. Disc Partition Systems Initializing a Disk The first file written to a new disk is the Disk signature it identifies the disk type and properties so Microsoft operating system can utilize the disk GPT is automatically selected If an additional Hard drive is installed the initialize disk dialog box will appear – Follow prompts Ch 9 and 1019

20. Disc Partition Systems Partitioning a Disk DOS used Fdisk DiskPart used since windows 2000 – Manages disk partitions and volumes – Used from command promt Disk Management: Preferred easy to use tool – Displays information about disk – Extend or shrink partition size – Add add’l drive and partitions – Format partitions – Change drive letters – Allocate amount of space each user can use – Run Chkdsk and disk defragmenter – Control Panel | Performance and Maintenance | Administrative Tools | Computer Management Ch 9 and 1020

21. Disc Partition Systems Disk Quota: limit on amount of disk space allocated to each user Dynamic Disk: can keep increasing size of a volume by adding additional disk drives Disk Mirroring – Two-way mirror data is duplicated across two drives – Three-Way mirror data is written across two drive and parity bits are written on third data can be written on new disk to automatically rebuild missing data Ch 9 and 1021

22. Disc Partition Systems Formatting a Disk Before it can be used a disk must be formatted (can also format flash drives) High-Level Format prepares disk to receive data (quick format) – Identifies sectors – Marks bad sectors – Erases context of data table Data still there but not easily recoverable without special software Low-Level Format (full format) – Actually destroys all data – Checks and marks bad sectors Ch 9 and 1022

23. Disk File Maintenance Two common tools used for disk maintenance Defragmenter and Chkdsk Defragmenter – Fragmented disks are when files are stored in non concurrent sectors /fragmented disks are slow – Disk become fragmented though normal operation of modifying, deleting and saving files – Run as routine maintenance – Accessories | System Tools | Disk Defragmenter Ch 9 and 1023

24. Disk File Maintenance Chkdsk is a utility that checks and repairs the integrity of the file system on the hard drive. It checks for: – bad sectors – Lost / bad clusters – cross linked files – Directory structure errors – Explorer | properties | tools | check now Performance Measures: benchmark tests are performance tests used to compare different hardware Ch 9 and 1024

25. PATA and SATA Hard Disk Interface ATA was a 16 bit used a 40 pin (later 80 pin) cable PATA (parallel ATA) (now refered to as IDE drive) integrated drive electronics or (EIDE Enhanced integrated drive electronics) – Motherboards usually have two IDE slots (IDE0 / IDE1) – Each slot (channel ) can support two physical drives – One drive must be designated master the other slave because they share a cable – Master slave are set by jumpers Ch 9 and 1025

26. PATA and SATA Hard Disk Interface SATA (serial ATA) uses a thin, flat or round cable with only 7 conductors Uses less space in case No master / slave Only one SATA drive per motherboard slot eSATA are hot swap devices Ch 9 and 1026

27. PATA and SATA Hard Disk Interface PATA (IDE DRIVE) CableSATA Cable Ch 9 and 1027