Computers, Measurement & Control
Flashcards for the FE Exam Morning Session content on computers, measurement and control
Terms in this set (135)
central processing unit (CPU) on a single chip
fetches and decodes the incoming instructions and generates the signals necessary for the arithmetic and logic unit to perform the intended function
arithmetic and logic unit (ALU)
executes commands and manipulates data
hold data and instructions for furhter manipulation in the ALU
program counter (PC)
a special register that always points to the address of the next instruction to be executed.
holds the current instruction during its execution
provide temporary data storage in sequential order--usually last in first out
the physical path along which the signal travels
logic path along which the signal travels
directs memory and i/o device transfers
carries the actual data and is the busiest bus
communicates control and status information
How do you determine how many words of memory can be addressed?
When there are n address lines in the bus, 2^n words of memory can be addressed
clock rate (ideal)
the number of instructions the mocroprocessor can execute per second
the speed of a microprocess is specified in ___
smallest changeable data unit (1 or 0)
8 bits; the smallest number of bits that can represent one alphanumeric character
8 & 16 bits; distinction depends on computer.
8, 16, & 32 bits; distinction depends on computer.
16, 32, & 64 bits; distinction depends on computer.
number of memory storage locations is always a mulitple of
VRAM; contains the text displayed on the screen of a terminal
holds the most recently read and frequently read data in memory
programmable read-only memory; initially blank but once filled cannot be changed.
erasable programmable read only memory; initially bland but can be filled, erased and refilled.
random access memory; easily changed memory.
electrically erasable PROM; can be erased with an electrical charge; similar to flash memory
memory lost when the power is turned off: RAM
data does not need to be refreshed and remains as long as the power stays on
data must be continually refreshed, Ex: DRAM
can run at much higher clock speeds than conventional memory. Higher than FPM, DRAM, and BEDO. up to 133 MHz.
type of DRAM developed by Rambus, Inc. transfers data at up to 800 Mhz
virtual memory (storage) VS
technique by which programs and data larger than main memory can be accessed by the computer. In virtual memory systems some of the disk space is used as an extension of the semiconductor memory.
a deadlock situation in which a program references a different page for almost every instruction, and there is not enough real memory to hold most of the virtual memory
direct memory access
DMA; a powerful I/O technique that allows peripherals to transfer data directly into and out of memory without affecting the CPU.
a technique used to ensure that the bits within a memory byte are correct.
the 8 bits of data plus their ninth parity bit
the parity bit will be set so there is an odd number of one-bits in the frame
the parity bit will be set so that there is an even number of one-bits in the frame
devices that feed data to, or receive data from, the computer
there are as many separate lines in the cable as there are bits in the code representing a character; an additional line is used as the strobe signal to carry a timing signal
all bits pass one at a time along a single line of cable
transmission speed (baud rate)
in bps is the number of bits that pass through the data line per second
small memories large enough to store information before it is used
handshaking (flow control)
peripherals sending status of its buffer to the computer
measure of the number of data bits stored per square inch of bits per track by the number of tracks per inch
average seek time
average time it takes to move a head from one location to a new location
rotational delay (latency)
time it takes to for a disk to spin a particular sector under the head for reading. on the average it is one half the time it takes to spin a full revolution
average access time
=rotational delay + average seek time
batch mode processing
programs are held and eventually grouped into efficient categories requiring the same peripherals and resources.
real-time (interactive processing)
a program runs when it is submitted, often with user interaction during processing
virtual machine (multitasking, multiprogramming)
each user on a machine simultaneously are allocating a piece of the main memory and runing applications simultaneously
a technique where each user takes turns using the entire computer main memory for a certain length of time.
program running in real-time
can be accomplished by segmenting the main computer memory
accessing the computer from a remote location
transmission is one way
data transmitted in both directions, but only one at a time
duplex or full duplex communcation
data can be transmitted in both directions simultaneously
asynchronus or start stop transmission
each character is preceded and followed by special signals
transmits a block of data continuously without pause and requires a built-in clock to maintain synchronization
LAN; many identical computers are linked together sharing storage and printer resources.
American Standard Code for Information Interchange (ASCII)
seven-bit code permitting 128 (2^7) different combinations.
Extended Binary Coded Decimal Interchange Code (EBCDIC)
widespread use in supercomputers. Uses eight bits (1 byte) for each character allowing a max of 256 (2^8)
a procedure consisting of a finite set of well-defined steps.
source code statements
human readable instructions found in an algorithm
if an executable program is kept on a disk or tape it is called _____
if the program is placed in ROM or EPROM
step-by-step drawing representing a specific procedure or algorithm
machine language instructions
intrinsically compatible and understood by the computer's CPU
more sophisticated programing
blocks of code that are to be repeated and are referred to by a symbolic name in source code
translates assembly language into machine language
program placed in computer's memory to run
performs checking and conversion functions on all instructions only when the compiler is invoked. a true standalone program is created
checks the instructions and converts them line by line into machine code during execution but produces no stand-alone program capable of being used without the interpreter.
a language is said to be this if subroutines and other procedures each have one specific entry point and one specific return point.
strong data types
a feature of a language if integers and real numbers cannot be combined in arithmetic statements
can be implemented on different machines
divides a procedure or algorithm into parts known as subprograms, subroutines, modules, blocks, or procedures.
when a subprogram calls itself
variables whose values are accessible strictly within the subprogram
can be referred to by the main program and all other subprograms
a set of instructions between the do until <condition> and the enduntil lines of code is repeated as long as the condition remains false.
set of instructions between the for <counter range> and the next <counter> lines of code is repeated for a fixed number of loops.
collection of fields
groups of records
sequential file structure
contains consecutive records and must be read starting at the beginning
indexed sequential file
one for which a separate index file is maintained to help locate records
random (direct access) file structure
any record can be accessed without starting at the begining of the file
place data in ascending or descending numerical or alphabetical order
a list is searched sequentially until the smallest element is found and brought to the top of the list that element is then skipped, and the remaining elements are searched for the smallest elelement.
total number of comparisons required for a successive minima technique
n(n-1)/2 or when n is large ~n^2/2
each element in the list is compared with the element immediately following it. If the first element is larger it is swapped. n^2/2 comparisons are needed on average swapping occures more frequently than successive minima so it is slower
elements are order by rewriting them in proper sequence. on average there are n^4/2 comparisons
complex method that reduces the average number of comparisons with random data to approximately nlog(n)/log(2)
maximum number of comparisons nlog(n)/log(2) but it is likely that even fewer will be needed
at worst n comparisons are required to find something on average n/2
one in which the list is in ascending or descending order and the middle element is searched first and one side is disregarded based on the result. number of required comparisons is log(n)/log(2)
method of finding storage location for a r/w operation not requiring an index file. Here the location can be calculated directly from the key
excellent results are obtained if n is a prime number poor if it is a power of 2.
attempt is made to use a record number that is already in use during hashing
has only one key field by which records can be located in a database
each record has an associated pointer to the next record in key sequence
usually a record number or memory address
How many pointers are changed when a record is added or deleted?
each record has one or more pointers to other records usually records that are lower and higher in the key sequence; number of comparisons required to find a record is 1+(log(n)/log(2))
records in a tree structure
contains records in an organized structured format according to one or more indexing schemes
stores all information in the equivalent matrix, nothing else is needed to find, read, edit, or select information (no pointers, indexing files, etc)
a machine implies that the machine is capable of absorbing and organizing new data, learning new concepts, reasoning logically, and responding to inquiries.
learn rules from sets of events that are entered whenever they occur.
any device used to convert a physical phenomenon into an electrical signal. Ex: microphone
the ratio of the change in electrical signal magnitude to the change in magnitude of the physical phenomena parameter being measured.
degree to which the sensitivity is in direct proportion to the parameter being measured
a measurement has greater if it is substantially unaffected by all variation outside of the measurer's control
repeatability of the measured results
stability (or insensitivity)
doesn't change due to minor changes in the measurement process
resistance temperature detectors (RTDs)
make use of changes in their resistance to determine changes in temperature
bonded strain gage
a metallic resistance device that is cemented to the surface of the unstressed member.
rosette strain gage
consists of two or more grids properly oriented for application as a single unit
Shannon's sampling theorem
a time-continuous signal is ocmpletely determined by its value at an infinite sequence of equally spaced times, if the frequency of sampling timesis greater than twice the highest frequency component of the signal.
Nyquist rate (f_N) for sampling a signal for analog to digital
is two times the highest frequency of interest.
frequencies greater than the sampling frequencies and at intereger multiples of the sampling frequency appear as lower frequencies