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71 terms

Computer chapter 1

STUDY
PLAY
ALU (arithmetic, logic unit)
Unit that perform arithmetic and logical operation
ASCII
a character coding system that uses seven bits and can represent 128 characters.
bit
Is the smallest unit of information a computer can work with.
Binary system
is the representation of ON and OFF of the computer. ON is represented by 1, and of by 0.
bus
in computing, is a set of physical connections (cables, printed circuits, etc.) which can be shared by multiple hardware components in order to communicate with one another. Commonly known as freeway.
Byte
, is a group of eight bits and is the method of representing one character of data, such as the essential numbers (0-9), or the basic letter of the alphabet, or punctuation symbols. A single unit of storage. If an essay needs 1375 characters and symbols, the computer need 1375 bites of storage to save that essay.
character code
perform conversion between the computer's bit patterns and the letters, numbers, and symbols on our keyboards called Characters.
character
the letters, numbers, and symbols on our keyboards called
ASCII (America Standard Code for Information Interchange).
What is the most widely used character code?
cache memory
is a small unit of ultrafast memory built into or near the processor that stores frequently or recently accessed program instructions and data. Faster than RAM but, also more expensive. this memoty is used by CPU to store instructions that are repeatedly reaquired to run programs improving overall system speed.
L 1 (primary cache)
cache memory level, is a unit of 4 KB to 16 KB of ultrafast memory included in the microprocessor chip that runs at approximately 10 nanoseconds.
L 2 (secondary cache)
cache memory level, is a unit of up to 512 KB of ultrafast memory that can be located within the microprocessor, but further from the registers than level 1 cache, or on a separate cache chip located on the motherboard very close to the microprocessor
L3
cache memory level, is found on some systems with newer microprocessors, like intel's xeon processor, that are located in some servers and workstation. It is located outside of the processor on a separate cache chip on the motherboard very close to the microprocessor.
chipset
motherboard component which is a collection of chips that work together to provide the switching circuitry needed by the microprocessor to move data throughout the computer.
memory
refers to the chips, located on the motherboard or within the CPU, that retain instructions an data to be accessed by the CPU.
Data dependency
when the CPU needs the results of a completed instruction to process the next one.
speculative execution
the processor executes and temporarily stores the next instruction in case it proves useful
branch prediction
the CPU tries to predict what will happen with the instruction.
Extended ASCII
A character coding system that uses 8 bits and allows 128 a additional characters, like the fractions and logical symbols, for a total of 256.
Gigabyte (GB)
one billion of bytes
hot swapping
the ability to connect and disconnect devices without shutting down the computer.
Fetch, decode, execute and store
four steps of the machine cycle
fetch and decode
machine cycle: intruction cycle two steps:
Execute and store
machine cycle: execution cycle two spteps:
fetch
retrives the next program instruction from the computer's RAM or cache memory
decode
determines what the program is telling the computer
execute
performs the requested action using the arithmetic logic unit (ALU) to perform arithmetic operations.
store
Keep the results to an internal register
Megabyte (MB)
one million of bytes.
Memory footprint
the amount of RAM that the program uses while it operates.
multitasking
, a process by which the CPU gives the user the illusion of performing instructions from multiple programs at once when in reality the CPU is rapidly switching between the programs and instructions.
parallel processing
another way to improve CPU performance is by using this process, a technique that uses more than one processor to execute a program, it usually is found on systems that run programs that perform a lot of computations, such as simulations or graphic processing software.
pipelining
a technique that feeds a new instruction into the CPU at every step of the processing cycle. Fetch, decode, execute and store.
RAM
, is volatile memory, which means it is not permanent and its contents are erased when the computer's power is switched off.
register
store data when it must be temporarily stored in the CPU.
ROM
a type of nonvolatile memory in which instructions are prerecorded and not erased when the system is shut down.
PROM
programmable read only memory that can be written on only once, but requires a special written device. It can not be erased and reused. It is used to hold startup programs that are bug free and are never meant to be changed.
EPROM
electrically programmable read only memory is erasable PROM than can be reused many times
EEPROM
electrically erasable programmable read only memory that can be rewritten many times while the chip is in the computer.
Flash EPROM
similar to an EEPROM except this ROM memory are erased in blocks, whereas regular EEPROMs erase one byte at a time.
system clock
electronic circuit that produces rapid pulses and coordinates the computer's internal activities.
clock speed
measurement of the electrical pulses generated by the system clock, usually measured in gigahertz (GHz).
System Unit
the box and house the computer's main hardware components.
motherboard, CPU, power supply, cooling fan, internal speaker, drive bays, expansion slots
System unit main components:
form factor
specifies how the internal components are located within the system.
tower case
a system unit case designed to sit on the floor next to a desk, provided the solution.
motherboard
is the large circuit board located within your system unit to which all other components are connected. Includes millions of transistors and carries electrical current. The most important components in the motherboard are CPU and RAM.
motherboard
provides the centralized physical and electrical connectivity to enable communication among these critical components.
Computer central processing unit (CPU)
is a chip located in the motherhood. It is the brain of the computer, is the central component of the computer
Instruction
an operation performed by the CPU and assigned a specific number
instruction set
the list of CPU instructions for the operations.
Control Unit and Arithmetic Logic Unit (ALU)
two subcomponent of the CPU
number of existing transistors, data bus width and word size, clock speed, operation per microprocessor cycle, use of parallel processing and type of chip.
what factors affect the perfomance of a CPU?
Terabyte
one trillion of bytes.
Unicode
a character code that uses 16 bits, can represent over 65,000 characters.
virtual memory
, the computer looks at RAM to identify data that has not been used recently and copies this data onto the hard disk. This free up space in RAM to load a new application or increase the space needed by a program currently in use.
word size
is the maximum number of bits the CPU can process at once.
connector
physical receptacle used to plug a peripheral device into the computer, example: telephone jack.
Port
electronically defined pathway used to send data into and retrieve data from the computer. Example: USB port.
USB 2.0
uses an external bus, supports data transfer rates of 480 Mbps between the computer and the peripheral device
Plug and play (PnP)
allows computers to automatically detect the device when you plug it in.
USB hub
Device that plugs into existing USB port, contains four or more additional ports.
VGA ( video graphics array)
• 15-pin male connector—works with standard monitor cables
• Transmits analog video signals
• Used for legacy technology cathode ray (CRT) monitors
DVI (digital visual interface) port
lets LCD monitors use digital signals
Onboard video
video circuitry built into the motherboard where the video connector is on the back of the system unit case
Fetch: retrives the next program intruction from the computer's RAM or cache momory.
Decode: determines what program is telling the computer to do.
execute: performs the requested action using the arithemetic logic unit to perform arithmetic operations.
Store: keep the results to an internal register.
List of four operations of the processing cycle and provide a brief description of theri functions
pippeling: feed of new intruction the CPU of every step of the processing cycle.
multitasking: CPU give the ilusion to the user of performing instruction from multiple programs at once, when the reality is CPU rapidely switch between the programs and instructions.
Parallel processing: a technique that use more than one processor to execute a program.
what are the difference beween pipelining, multitasking and parallel processing?
Register, L2,L1, RAM, hard disk.
place the followint hardware in order from the one with the faster access speed to the one with the slowes access speed: Level 1 cache, Level 2 cahce, RAM, register, hard disk
Cache improve memory system, because CPU retrives data more quickly from cache memory than from RAM.
why is importatn to have some amount of cache on a system today?
Control Unit: under the direction of an embedded program, switches from one stage to the next and performs the action of that stage. and ALU
List two subcomponents of the CPU and explain.
control unit
under the direction of an embedded program, switches from one stage to the next and performs the action of that stage