Chapter 1 Notes
RGB Encoding
- A method of defining a pixel's color and brightness in terms of intensity of the colors red, green, and blue
Radix Point
- The point that divides the fractional portion from the whole portion of a number; in the decimal numbering system, it's referred to as a decimal point
3 uses of Flip-flops
1. It demonstrates how devices can be constructed from gates, a process known as digital circuit design. 2. Provides an example of abstraction and the use of abstract tools. 3. It is one means of storing a bit within a modern computer. More precisely, a flip-flop can be set to have the output value of either 0 or 1.
Sign bit
A binary bit that is added to the leftmost position of a binary number to indicate whether that number represents a positive or a negative quantity.
Transistors
A device that acts, depending on the voltage level of an input signal, either as a wire that conducts electricity or as a resistor that blocks the flow of electricity. It has no moving parts. Made of a Semiconductor material, like copper.
Gate
A device that produces the output of a Boolean Operation when given the operations input values. Can be constructed from a variety of technologies such as gears, relays, and optic devices. Inside today's computers they are usually implemented as small electronic circuits in which the digits "0" and "1" are represented as voltage levels.
Text File
A file consisting of a long sequence of symbols encoded using ASCII or Unicode
Excess Notation
A format that can be used to represent signed integers with a fixed numbers of bits; essentially, it divides a range of ordinary binary numbers in half and uses the lower half for negative values and the upper half for nonnegative values.
Main Memory
A large collection of circuits (such as Flip-flops), each capable of storing a single bit. This bit reservoir is know as the machine's Main Memory.
Stream
A long string of bits.
Floating-point notation
A method for representing real numbers that consists of two parts: a mantissa and an exponent; the mantissa holds the bits that are interpreted to derive the real number's digits, and the exponent value indicates the radix point's position.
Byte
A string of 8 bits is called a byte. Thus, a typical memory cell has a capacity of one byte.
Hard Disk Drive or Magnetic Disk
A thin spinning disk with magnetic coating is used to hold data.
Musical Instrument Digital Interface (MIDI)
A way of encoding the sheet music read by a performer rather than the performance itself, and in turn the MIDI "recording" can sound significantly different when performed on different synthesizers.
Two's Complement
A way of representing negative numbers in binary, the first digit can represent either 0 or -128, which the other numbers add onto If negative numbers are represented in twos complement form then computers don't need circuitry to perform subtraction; they can just add a negative value instead
Binary Notation
A way of representing numeric values using only the digits 0 and 1 rather than the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 as in the traditional decimal, or base 10, system.
Boolean Operation: AND
AND Operation represents the truth or falseness of the compound statements components; the output represents the truth or falseness of the compound statement itself. Since a statement of the P AND Q is true only when both of its components are true, we conclude that 1 AND 1 should be 1, whereas all other cases should produce an output of 0.
Mass Storage (Secondary Storage)
Additional memory devices. These systems could be magnetic disks, CD's, DVD's, magnetic tapes, flash drives, and solid-state disks.
Signed Numbers
All numbers on the number line except zero are signed numbers either positive or negitive zero is negather positive or negative
ANSI
American National Standards Institue
ASCII
American Standard Code for Information Interchange
Optical Sytems
Another class of mass storage systems applies optical technology.
Digital Versatile Disks (DVD)
Are constructed from multiple, semi-transparent layers that serve as distinct surfaces when viewed by a precisely focused laser, providing storage capacities of several GB.
Flash Memory
Bits are stored bu sending electronic signals directly to the storage medium, where they cause electrons to be trapped in tiny chambers of silicon dioxide, thus altering the characteristics of small electornic circuits. Since these chambers are able to hold their captive electrons for many years without external power, this technology is excellent for portable, nonvolatile data storage.
Compact Disk-Digital Audio (CD-DA
CD technology was originally applied to audio recordings using a recording format known as this
Secure Digital Extended Capacity Memory Cards (SDXC Memory Cards)
Can exceed a TB.
Secure Digital High Capacity (SDHC) Memory Cards
Can provide up to 32GBs
Read Operation
Circuits can get data from the memory by electronically asking for the contents of a certain address.
Unicode Transformation Format 8-bit (UTF-8)
Code using a unique pattern of up to 21-bits to represent each symbol. when combined with the UNICODE the original ASCII cahracters can still be represented with 8-bits while the thousands of additional characters from various languages can be represented by 16-bits. Uses 24- or 32 bits patterns.
Boolean Operation: OR
Continuing with P which represents one statement and Q represents another. Such statements are true when at least one of their components is true.
Unicode
Created to support the computing community Pronounced "YOU ni code" uses 16-bits and provides codes for 65,000 characters. Such as to represent the many different alphabets and languages of the world.
Compact Disk
Disks that are 12 centimeters (approximately 5in) in diameter and consist of reflective material covered with a clear protective coating. Information is recorded on them by creating variations in their reflective surfaces. This information can then be retrieved by means of a laser that detects irregularities on the reflective surface of the CD as it spins.
Cylinder
Each time the read/write heads are re-positioned, a new set of tracks- becomes accessible.
Sectors
Each track is divided into small arcs called this. This allows information to be recorded as a continuous string of bits.
Word Processors
Elaborate files using programs like Microsoft Word.
Optical Zoom
Enlarging an image by adjusting the camera lens.
Pixel Luminance
Essentially the sum of the red, green, and blue components.
Flash Drives
Flash memory devices with capacities of hundred of GBs, are available for general mass storage applications.
Rotation Delay or Latency Time
Half the time required for the disk to make a complete rotation, which is the average amount of time required for the desired data to rotate around to the read/write head once the head has been positioned over the desired track.
Zoned-bit recording
In high-capacity disk storage systems, the tracks near the outer edge are capable of containing significantly more sectors than those near the center. This capability is often used by applying a technique called this.
Magnetic Tape
In which information is recorded on the magnetic coating of a thin plastic tic tape wound on reels.
ISO
International Organization for Standardization.
Boolean Operation: NOT
Its output is the opposite of that input; if the input of the operation NOT is true, then the output is false, and vice versa. Thus, if the input of the NOT operation is the truth or falseness of the statement Fozzie is a bear. then the output would represent the truth or falseness of the statement Fozzie is not a bear
Solid-State Disks
Larger flash memory devices, are explicitly designed to take the place of magnetic hard disks.
Most Significant Bit
Left most bit, if the contents of the cell were interpreted as representing a numeric value. this bit would be the most significant digit in the number.
Pixel (Picture Element)
One means of representing an image is to interpret the image as a collection of dots
Boolean Operations
Operations that manipulate True/False (1 being true/0 being false) values
Write Operation
Or they can record information in the memory bu requesting that a certain bit pattern be placed in the cell at a particular address
Blue-ray Disk (BDs)
Provide over 5 times the capacity of a DVD. This seemingly vast amount of storage is needed to meet the demands of high definition video.
Secure Digital (SD) Memory Cards (SD Cards)
Provide up to 2GBs of storage and are packaged in a plastic rigged wafer about the size of a postage stamp. (SD Cards are also available in smaller mini and micro sizes.)
Track
Read/write heads are places above and/or below the disk so that as the disk spins, each head traverses a circle called this.
Zones
Several adjacent tracks. Each typical disk contains approximately 10 zones.
Text Editors
Simple text files that are manipulated by utility programs called this
Floppy Disk Drivers
Single platters with a magnetic coating are encased in a portable cartridge designed to be readily removed from the drive.
Von Neumann Architecture
Structure and organization of virtually all modern computers are based off this design. Consists of 3 major characteristics. 1 - Four major subsystems called memory, input/output, arithmetic/logic unit, and control unit. 2 - stored program concept. 3 - sequential execution of instructions
AND, OR, XOR, NOT, NAND, NOR
The Boolean Operations. These are similar to the arithmetic operations TIMES and PLUS because they combine
Random Access Memory (RAM)
The ability to access cells in any order, a computer's main memory is often called this. Or they can record information in the memory by requesting that a certain bit pattern be placed in the cell at a particular address. Dynamic RAM (DRAM) Synchronous DRAM (SDRAM)
Bit Map
The appearance of each pixel is then encoded and the entire image is represented as a collection of these encoded pixels.
Kibi-, Mebi, Gibi-, and Tebi-bytes
The correct terminology for powers of 1024. As a general rule of thumb Kilo, Mega, Etc.. refer to powers of two. When used in the context of computer measurements, but they refer to powers of a thousand when used in other contexts.
High-order End
The left end of the row.
Transfer Rate
The rate at which data can be transferred to or from the disk.
Low-order End
The right end of the row.
Least Significant Bit
The rightmost bit is referred to as this.
Access Time
The sum of seek time and rotations delay.
Seek Time
The time required to move read/write heads from one track to another.
Address
To identify individual cells in a computer's main memory, each cell is assigned a unique "name," called its address. The system is analogous to the technique of identifying houses in a city by addresses. In the case of memory cells, however, the addresses used are entirely numeric. To be more precise, we envision all the cells being placed in a single row and numbered in this order starting with the value zero. Such an addressing system not only gives us a way of uniquely identifying each cell but also associates an order to the cells giving us phrases such as "the next cell" or "the previous cell."
Hexadecimal notation
Uses a single symbol to represent a pattern of 4bits. For example, a string of twelve buts can be represented by three hexadecimal symbols. 1011= B 0101= 5
ASCII Code
Uses bit patterns of length seven to represent letters of the English alphabet., punctuation symbols, the digits 0-9, and certain control information such as line feeds, carriage returns and tabs. Can provide 128 additional bit patterns.
Memory Cell
Usually envisioned as being arranged in a Row with a High-order end, Low-order end, Most significant bit, and Least significant end.
Head Crash
When a spec of dust is jammed between the head and disk surface, destroying both.
Very Large-scale Integration (VLSI)
Which allows millions of electrical components to be constructed on a wafer (called a chip), is used to create miniature devices containing millions of flip-flops along with their controlling circuitry.
Cells
a manageable unit within the Main Memory. Typical Cell size being 8 bits
Bits (Binary Digits)
computers information encoded as patterns of 0's and 1's.
Refresh Circuit
device circuitry that repeatedly replenishes the charges many times a second.
Computer-aided Design (CAD)
drawings of three-dimensional objects are displayed and manipulated on computer display screens.
Digital Zoom
enlarging an image by making the pixels bigger, leads to a grainy appearance.
Flip-flop
is a fundamental unit of computer memory. It is a circuit that produces an output value of 0 or 1, which remains constant until a pulse (a temporary change to a 1 that returns to 0) from another circuit causes it to shift to the other value.
LZW Compression
is the compression of a file into a smaller file using a table-based lookup algorithm invented by Abraham Lempel, Jacob Ziv, and Terry Welch. Two commonly-used file formats in which LZV compression is used are the GIF image format served from Web sites and the TIFF image format.
Overflow
is the problem that occurs when a computation produces a value that falls outside the range of values that can be represents.
Boolean Operatoin: XOR
produces an output of 1 (true) when one of its inputs is 1 (true) and the other is 0 (false). For example, a statement of the form P XOR Q means "either P or Q but not both." (In short, the XOR operation produces an output of 1 when its inputs are different.)
