Tech Guide 1

Bit

The smallest element of computer data is a called a binary digit
It can be either a zero or a one.

Byte

equal to 8 bits.
represents one number or character.
Thus, if a computing device has 100 million bytes of memory, it can hold 100 million characters.
Computer storage is measured in bytes.

Megabyte

1 million bytes = ~ one small novel

Terabyte

1 trillion bytes = 1K copies of Encyclopedia

Hard Disk Drive (HDD) vs. Solid Disk Drive (SDD)

Hard disk drives are bigger, less durable, and less efficient, but they are cheaper.
Solid Disk Drives are faster, more compact, more durable, but they are pricier.

Random Access Memory (RAM)

The part of primary storage that holds a software program
and small amounts of data when they are brought from secondary storage.

Central Processing Unit (CPU)

manipulates the data and controls the tasks performed by the other components.
performs the actual computation or “number crunching”
inside any computer.

CPU Control Unit

sequentially accesses program instructions, decodes them and controls the flow of data to and from the ALU, the registers, the caches, primary storage, secondary storage and various output devices.

CPU Arithmetic Logic Unit (ALU)

performs the mathematic calculations and makes logical comparisons.

Cache

A type of primary storage where the computer can temporarily store blocks of
data used more often.

Primary Storage

or main memory stores three types of information for very brief periods of time:
Data to be processed by the CPU;
Instructions for the CPU as to how to process the data;
Operating system programs that manage various aspects of the computer’s operation.
____________ takes place in chips mounted on the computer’s main circuit board, called the motherboard.

Secondary Storage

Memory capacity that can store very large amounts of data for extended periods of time.
Magnetic tape (sequential access)
Magnetic disks (direct access)
Solid State Drives (SSDs)
Optical storage devices (Blue Ray, DVD, CD)
Flash memory (memory cards, thumb drives)

Input Technologies

Human data-entry - Require human effort
e.g. Keyboard, mouse pointing stick, trackball, joystick, touchscreen, stylus, and voice recognition

Source-data automation - Input data with minimal human intervention (e.g., barcode reader)
Speed up data collection
Reduce errors
Gather data at source of event or transaction

Output Technologies

generated by a computer can be transmitted to the user over several output devices and media, which include:
Monitors
Printers
Plotters
Voice
Retinal scanning devices

Communication Technologies

provide for the flow of data from external computer networks (e.g. the Internet and intranets) to the CPU, and from the CPU to computer networks.

Hard Drive - how measured?

measured in gigabytes

Megahertz - how measured?

measures computer processing speed

Moore's Law

the number of transistors on a silicon chip roughly doubles every two years, the performance and capabilities of computers will continue to increase while the price of computers decreases. It is a prediction made by American engineer Gordon Moore in 1965.

Read Only Memory (ROM)

Type of primary storage where certain critical instructions are
safeguarded; the storage is nonvolatile and retains the instructions when the power to the computer is turned off.