HARD-DISK/CD/MOUSE/KEYBOARD

HARD DISK DRIVES 
Reynold B. Johnson
is said to be the "father" of the disk drive

The two most common form factors for modern HDD's are  
3.5-inch in desktop computers  
2.5-inch in laptops

The first IBM drive
350 RAMAC

HDDs were called fixed disk drives

FAT or FAT32 (File Allocation Table)
NTFS (New Technology File System)
Solid State Drives (SSDs)

BAD SECTORS
are little clusters of data on your hard disk that cannot be read

SECTOR
is simply a unit of information stored on your hard disk

There are various problems that can cause HDD bad sectors:
•Improper shutdown of Windows;
•Defects of the hard disk, including general surface wear, pollution of the air inside the unit, or the head touching the surface of the disk;
•Other poor quality or aging hardware, including a bad processor fan, dodgy data cables, an overheated hard drive;
•Mal ware

HARD BAD SECTORS
are the ones that are physically damaged (that can happen because of a head crash)

SOFT BAD SECTORS
they are logical errors, not the physical ones

CD "COMPACT DISC"
JAMES T. RUSSELL. In the late 1960s, Russell created a system that recorded, stored, and played audio/video data using light.

PHILIPS AND SONY released the first of the compact disc (CD) formats, which they then called CD-DA (digital audio)

DVD Digital Versatile Disc

CD's and DVDs are types of optical storage media

The two main advantages of optical storage media are *greater data density
*increased stability

HOW BIG IS THE STANDARD CD?
diameter of 120 millimeters(STANDARD)
diameter of 40 millimeters(MINI)

APPROXIMATELY HOW MANY MINUTES OF MUSIC CAN BE STORED ON A CD?   
74min

IN WHAT 'DIRECTION' IS DATA STORED ON A CD?
inside to outside. A CD has a single spiral track of data, circling from the inside of the disc to the outside If the data track of a CD were stretched out in a line,

FOR STANDARD MUSIC REPLAY, HOW FAST DOES A CD SPIN WHEN BEING READ?  
200 - 500 rpm.

HOW THICK IS A CD?  
1.2 mm.

APPROXIMATELY HOW MANY BYTES OF DATA CAN BE STORED ON A CD?  
0.75 gigabytes

WHAT IS USED TO READ THE DATA OFF OF THE DATA TRACK OF A CD?   
Laser.

GOLD DISCS use gold in place of the standard aluminum reflective coating to provide greater longevity and reduce CD rot. Typically coveted by audiophiles in CLASSICAL, OPERA and JAZZ music.

MOUSE
Manually Operated User Selection Equipment

Douglas Engelbart
The first computer mouse, held by inventor

Tom Cranston 
The world's first trackball invented by

Mickeys per second
is a unit of measurement for the speed and movement direction of a computer mouse

One mickey is approximately 1/200th of an inc

KEYBOARD
Christopher Latham Sholes
Invented the modern form of typewriter 

Mathew Roper
Invented the concept of QWERTY

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