Computer Performance
& Storage Devices
Computer Performance
Boot Process

Sequence of events that occurs
between the time you turn on a
computer and the time that it becomes
ready to accept commands.

Purposes
• Runs a diagnostic test to make sure
everything is working.
• Loading the operating system, so the
computer can carry out basic operations.
6 events of the boot process:
1.
2.
3.
4.
5.
6.
Power up
Start boot program
Power-on self-test
Identify peripheral devices
Load operating system
Check configuration and
customization
Circuits


The path from one
component of a
computer to another
that data uses to
travel.
Circuits run between


RAM and the
microprocessor
RAM and various
storage devices
Silicon Chip


Silicon is melted
sand.
What the circuits
are embedded into
to keep them
together.
Megahertz (mHz)



A measurement used
to describe the speed
of the system clock.
A megahertz is equal
to one million cycles
(or pulses) per second.
1.3 GHz means that
the microprocessor’s
clock operates at a
speed of 1.3 BILLION
cycles per second.
RAM vs. ROM

RAM




“Random Access
Memory”
The ability of a storage
device to go directly to a
specific storage location
without having to search
sequentially from a
beginning location.
Very volatile
• Cannot hold data when
the power is off.
• Looses all data when
power is lost.
ROM



“Read only memory”
Drives can read data
from disks, but cannot
store new data on them.
One or more integrated
circuits that contain
permanent instructions
that the computer uses
during the boot process.
Binary Number System

A method for
representing letters
or numbers using
only two digits, 0 and
1.

Bit
• Each 0 or 1

Byte
• 8 bits

Also referred to as
Base 2 Binary
Code.
Memory Measurements

Bit


Byte




Approximately 1 billion
bytes
Terabyte


Approximately 1 million
bytes
Exactly 1,048,576 bytes
Gigabyte


Approximately 1,000 bytes
Exactly 1,024 bytes
Megabyte


8 bits
Kilobyte


Each 0 or 1
Approximately 1 trillion
bytes or 1024 gigabytes
Petabyte

1024 Terabytes
Storage Devices


Used to keep data when the
power to the computer is
turned off.
Medium/media

Location where data is
stored.
Hard Disk


Usually mounted
inside the
computer’s system
unit.
Can store billions
of characters of
data.

Stated in forms of
bytes:
• Gigabytes,
Terabytes or
Petabytes
USB or Flash Drive

A flash memory card that plugs into the
computer's USB port. Small enough to hook
onto a keychain, it emulates a small disk
drive and allows data to be easily transferred
from one machine to another.
• Also known as a "flash drive," "pen drive," "keychain
drive," "key drive," "USB key," "USB stick" and "memory
key," numerous brand names have also been coined
such as Lexar's JumpDrive and Trek 2000
International's ThumbDrive.
Portable Hard drive

A disk drive that is plugged into an external port
on a computer such as USB.

Typically used for backup, but also as secondary
storage, such units rival internal drives in capacity.
For laptops, the PC Card slot may be used to connect
a cable to a full-size drive, or the hard disk may be
contained entirely inside the PC Card.
CD-ROM


“CD – Read Only Memory”
Also called CD-R


CD-Read
Storage device that uses
laser technology to read
data that is permanently
stored on compact disks,
cannot be used to write data
to a disk.
CD-RW



“CD-Read Write”
A storage device that reads data from CD’s and also
can write data to CD’s.
Similar to a CD-ROM, but has the ability to write to
CD.
DVD-ROM



“Digital Video Disks
– Read Only
Memory”
Reads data from
CD’s (audio and
data) and DVD’s
(data or movie)
Cannot be used to
write data to a disk.
Resources
Parsons, June Jamrich, and Dan Oja.
Computer Concepts. Boston: Course
Technology - Thompson Learning,
2002.