1- Assembler
A program that converts symbolically-coded programs into object level, machine code. In an assembler program, unlike a compiler, there is a one-to-one correspondence between human-readable instructions and the machine-language code.
2 - Compiler
A program that translates human-readable programs into a form the computer understands. The input (source code) to the compiler is a description of an algorithm in a problem- oriented language; its output (object code) is an equivalent description of the algorithm in a machine-oriented language
3 - Bandwidth
A piece of the spectrum occupied by some form of signal, where it is television, voice, fax data, etc.. Signals require a certain size and location of bandwidth in order to be transmitted. The higher the bandwidth, the faster the signal transmission, and thus allowing for a more complex signal such as audio or video. Because bandwidth is a limited space, when one user is occupying it, others must wait their turn. Bombarding the Internet with unnecessary information is referred to as "taking up bandwidth."
4 - Batch processing
Originally, a method of organizing work for a computer system, designed to reduce overhead by grouping similar jobs. In one scheme, jobs were collected into batches, each requiring a particular compiler. The compiler was loaded, and the jobs submitted in sequence to the compiler. The term has come to be applied to background processing of jobs not requiring user intervention on multiuser systems.
5 - Broadband
A communications medium on which multiple signals are simultaneously transmitted at different frequencies. Also refers to switching capability implemented on this medium that allows communication between devices connected to it. In telecommunications it is defined as any channel with a bandwidth greater than voice grade (4 KHz).
6- Debug
To detect, trace and eliminate errors in computer programs.
7 - Ethernet
A local area network originally developed by Xerox for linking personal computers. Later adapted by DEC and Intel as well and subsequently adopted as an international standard called 802.3. It transmits data at 10 megabits per second. All computers on a network were originally connected to a coaxial cable up to one kilometer. Each computer monitors all transmissions, looking for packets containing its identifier as the destination. Only one signal may be present on the channel at a time and no single computer controls transmissions. Several upper layer protocols, such as DECnet and TCP/IP use Ethernet as an underlying transport mechanism. Ethernet is to be contrasted with other data link protocols such as token ring, DDCMP or SDLC. Uses CSMA/CD.
8 - Fiber optics
A high speed channel for transmitting data. Made of high-purity glass sealed within an opaque tube. Much faster than conventional copper wire such as coaxial cable.
9 - FAQ
Frequently Asked Questions. A collection of information on the basics of any given subject. Often put together and archived on a server so that people don't waste bandwidth asking simple questions.
10 - FTP
File Transfer Protocol. A program that allows for file transfers over the Internet.
11 - Hardwired
Circuits that are permanently interconnected to perform a specific function, as distinct from circuits addressed by software in a program and, therefore, capable of performing a variety of functions, albeit more slowly. Also used to describe a non-switched connection between devices.
12 - Hierarchical file
A hierarchical file is one that contains information collected on multiple units of analysis where each unit of analysis is subordinate to another unit. For example, if the physical housing structure is one unit, and individual persons within the structure is another unit, the person records are subordinate
13 - Hierarchical file structure
A format for storing hierarchical files . Each unit of analysis has its own record structure or record type . Different units of analysis do not necessarily have the same number of bytes or characters as the records for other units of analysis. In order to give such a file a common physical record length , short logical records are typically "padded" with blanks so that they will all be the same physical record length. A hierarchical file can be also be stored in a rectangular file . For instance, the Survey of Income and Program Participation is distributed both ways; users can choose the format they prefer. Typically, the hierarchical file structure is more space-efficient but more difficult to use.
14 - Hub
A device that is a center of network activity because it connects multiple networks together
15 - ISDN
Integrated Services Digital Network. An international communications standard for a common interface to digital networks that allows the integration of voice and data on a common transport mechanism. Proposed by Bellcore for transmission of data, voice and higher-bandwidth technologies over phone lines.
16 - JPEG
Joint Photographic Experts Group. The ISO proposed standard for compression of digital data, especially 24-bit color images. It is lossy in that it reduces the file size at the expense of image quality. PostScript Level 2 color printers are supposed to be able to receive, decompress and print JPEG compressed images. Uses quantization and Huffman encoding.
17 - Modem
Short for MOdulation/DEModulation, it is a device that can convert a digital bit stream into an analog signal (modulation) and can convert incoming analog signals back into digital signals (demodulation). The analog communications channel is typically a telephone line and the analog signals are typically sounds.
18 - Mosaic
An Internet-based, global hypermedia browser that provides a unified interface to the various protocols, data formats, and information archives (i.e. gopher) used on the Internet and enables powerful new ways for discovering, using, viewing, and sharing information. It was developed by NCSA as part of the WWW project.
19 - Ping
Packet Internet Groper. Probably originally contrived to match the submariners term for a sonar pulse.
n. Slang term for a small network message (ICMP ECHO) sent by a computer to check for the presence and aliveness of another.
v. To verify the presence of. To get the attention of.
20 - Router
A device connecting separate networks that forwards a packet from one network to another based only on the network address for the protocol being used. For example, an IP router looks only at the IP network number.
21 - SPARC
Scalable Processor ARChitecture. Trademark of SunMicrosystems 32-bit RISC microprocessor architecture. The architecture is open in the sense that other vendors can obtain the processor chips and documentation sufficient to build computers using it.
22 - SQL
Structured Query Language. ANSI standard data manipulation language used in most relational data base systems. A language for requesting data from a relational database.
23 - URL
Uniform Resource Locater. A scheme used to locate a document accessible over the Internet.
24 - CMOS--- Complementary Metal-Oxide Semiconductor
25 - BIOS--- Basic Input Output System
26 - USB--- Universal Serial Bus
27 - ATM--- Automatic Teller Machine
Showing posts with label TECH INFORMATION. Show all posts
Showing posts with label TECH INFORMATION. Show all posts
Tuesday, April 28, 2009
Information about LCD
Lcd means"liquid crystal display"
lcd is mainly divided into 6 parts
1> virtical polarizer
2>vertical conductor
3>liquid crystals>
4>horizontal conductor
5>horizontal polarizer
6>reflective layer
advantages:
1>low cost
2>less power consumption
3>it requires less space coz screen is totaly flat
4>low weight
5>produce littile heat
disadvantages:
1>low quality resolution
2>lower contrast
3>not suitable 4 use in dark envoirment
lcd is mainly divided into 6 parts
1> virtical polarizer
2>vertical conductor
3>liquid crystals>
4>horizontal conductor
5>horizontal polarizer
6>reflective layer
advantages:
1>low cost
2>less power consumption
3>it requires less space coz screen is totaly flat
4>low weight
5>produce littile heat
disadvantages:
1>low quality resolution
2>lower contrast
3>not suitable 4 use in dark envoirment
INFORMATION ABOUT AUDIO CD AND MP3 CD
Audio CD
An audio CD (Compact Disc Digital Audio) is one that you buy from stores and contains only audio tracks. You can play an audio CD in any CD players, including your car CD player, and your computer CD-ROM. The standard for Audio CDs is called "Red Book".
The audio tracks are uncompressed digital data (essentially WAV). When you look at the contents of an audio CD, you may notice the files are .CDA files. A CDA file simply points to the location of the audio track on the CD. You cannot just copy these CDA files to another location since they are just "pointer" files, contain no audio data. The actual audio data is stored on the CD sectors and cannot be viewable on your computers.
An audio CD normally can hold up to 74 or 80 minutes of audio. So when you create an audio CD from some MP3 files, for example, no matter how big or small your mp3 files are, the CD can only fit in up to 80 minutes of audio.
Pro & Con
Audio CD is a very first generation of digital audio compact disc and because of this, audio CD can be played on any CD players.
However, an audio can only hold up to 80 minutes of audio. This is about 10-15 songs if the average length of the songs are 4-5 minute. Not much at all! if you want to put more songs onto a CD, you'll an MP3 CD.
The frequency response: from 20 Hz to 20 kHz.
Bit rate = 44100 samples/s × 16 bit/sample × 2 channels = 1411.2 kbit/s (more than 10 MB per minute)
Sample values: range from -32768 to +32767.
On the disc, the data are stored in sectors of 2352 bytes each, read at 75 sectors/s.
MP3 CD
An Mp3 ("MPEG-1 Audio Layer 3") file is just like a computer data file. The Mp3 format is audio encoding format, sometimes called "compressed" format. The Mp3 format was invented by a team of European engineers at Philips and became an ISO/IEC standard in 1991.
Late 1990s, the internet users started to encode more and more audio files using the Mp3 format and spread them over the internet. This lead to the creations of many Mp3 player software such as WinAmp, Nullsoft, etc... The Mp3 format became the most popular audio format for computer because of the advantages of it.
You can compress an audio track from 40-50 MB to create an mp3 file of 4-5 MB with the same quality. Well, the quality actually depends on the encoding methods. The low bit-rate would give you a smaller Mp3, but with lower quality.
Pros & Cons
An Mp3 CD can hold up to 700 MB of data/mp3 files. If you have Mp3 files with an average of 4-5 MB each, for example, you can store up to 160 songs on a CD, about 10 times of an Audio CD.
However, not all CD players can play Mp3 CD. More and more CD players are now Mp3 compatible, but not all of them. So you might need to question yourself when you want to create an Mp3 CD; for example, if the target CD player can handle it.
An audio CD (Compact Disc Digital Audio) is one that you buy from stores and contains only audio tracks. You can play an audio CD in any CD players, including your car CD player, and your computer CD-ROM. The standard for Audio CDs is called "Red Book".
The audio tracks are uncompressed digital data (essentially WAV). When you look at the contents of an audio CD, you may notice the files are .CDA files. A CDA file simply points to the location of the audio track on the CD. You cannot just copy these CDA files to another location since they are just "pointer" files, contain no audio data. The actual audio data is stored on the CD sectors and cannot be viewable on your computers.
An audio CD normally can hold up to 74 or 80 minutes of audio. So when you create an audio CD from some MP3 files, for example, no matter how big or small your mp3 files are, the CD can only fit in up to 80 minutes of audio.
Pro & Con
Audio CD is a very first generation of digital audio compact disc and because of this, audio CD can be played on any CD players.
However, an audio can only hold up to 80 minutes of audio. This is about 10-15 songs if the average length of the songs are 4-5 minute. Not much at all! if you want to put more songs onto a CD, you'll an MP3 CD.
The frequency response: from 20 Hz to 20 kHz.
Bit rate = 44100 samples/s × 16 bit/sample × 2 channels = 1411.2 kbit/s (more than 10 MB per minute)
Sample values: range from -32768 to +32767.
On the disc, the data are stored in sectors of 2352 bytes each, read at 75 sectors/s.
MP3 CD
An Mp3 ("MPEG-1 Audio Layer 3") file is just like a computer data file. The Mp3 format is audio encoding format, sometimes called "compressed" format. The Mp3 format was invented by a team of European engineers at Philips and became an ISO/IEC standard in 1991.
Late 1990s, the internet users started to encode more and more audio files using the Mp3 format and spread them over the internet. This lead to the creations of many Mp3 player software such as WinAmp, Nullsoft, etc... The Mp3 format became the most popular audio format for computer because of the advantages of it.
You can compress an audio track from 40-50 MB to create an mp3 file of 4-5 MB with the same quality. Well, the quality actually depends on the encoding methods. The low bit-rate would give you a smaller Mp3, but with lower quality.
Pros & Cons
An Mp3 CD can hold up to 700 MB of data/mp3 files. If you have Mp3 files with an average of 4-5 MB each, for example, you can store up to 160 songs on a CD, about 10 times of an Audio CD.
However, not all CD players can play Mp3 CD. More and more CD players are now Mp3 compatible, but not all of them. So you might need to question yourself when you want to create an Mp3 CD; for example, if the target CD player can handle it.
Information about COMPUTER BIOS
At times a Computers BIOS and its Drivers will need to be updated. This is usually true with older computers because with the arrival of new technology, new standards will arise, and the BIOS and Drivers will need to change in order to understand the new hardware. A driver is a software program that controls a device. Every device like a printer, disk drive or keyboard has a driver.
Whenever you startup a computer, the first thing you see is the BIOS software running. To enter the BIOS setup you will have to press a certain key or combination of keys in the initial startup screen (Esc, Del, Ctrl-Esc, F2, F1, Ctrl-Alt-Esc, ect…). There is usually a command line that shows up. When it does, press the specified key or keys to enter setup. Depending on the BIOS manufacturer you will see a number of options. (Examples: time/date, memory, plug and play, security, power management, boot sequence, drive configuration, exit, ect…) Be cautious when making changes to the setup. Some changes can cause the computer to not boot properly. When you finish you should save your settings and exit. The BIOS should restart your computer and the new settings should take effect.
The BIOS (Basic input/output system) is software that is usually stored on a flash memory chip and is located on the motherboard. What BIOS does is make sure that the CPU, hard drive(s), ports, and other chips in the computer work together. BIOS plays a huge part in starting up a computer. The BIOS provides the CPU with the instructions to start the operating system. A computer might have more than one bios chip. For example: A video card might have its own bios chip installed. The BIOS is in charge of setting up and managing things like the monitor, keyboard, and other ports on the computer especially when the computer system is starting up. Upon starting a computer system, the bios runs a POST (Power on self test) to check all of the hardware components to make sure they are functioning properly.
Whenever you startup a computer, the first thing you see is the BIOS software running. To enter the BIOS setup you will have to press a certain key or combination of keys in the initial startup screen (Esc, Del, Ctrl-Esc, F2, F1, Ctrl-Alt-Esc, ect…). There is usually a command line that shows up. When it does, press the specified key or keys to enter setup. Depending on the BIOS manufacturer you will see a number of options. (Examples: time/date, memory, plug and play, security, power management, boot sequence, drive configuration, exit, ect…) Be cautious when making changes to the setup. Some changes can cause the computer to not boot properly. When you finish you should save your settings and exit. The BIOS should restart your computer and the new settings should take effect.
The BIOS (Basic input/output system) is software that is usually stored on a flash memory chip and is located on the motherboard. What BIOS does is make sure that the CPU, hard drive(s), ports, and other chips in the computer work together. BIOS plays a huge part in starting up a computer. The BIOS provides the CPU with the instructions to start the operating system. A computer might have more than one bios chip. For example: A video card might have its own bios chip installed. The BIOS is in charge of setting up and managing things like the monitor, keyboard, and other ports on the computer especially when the computer system is starting up. Upon starting a computer system, the bios runs a POST (Power on self test) to check all of the hardware components to make sure they are functioning properly.
Information about RAM (RANDOM ACCESS MEMORY)
RAM (Random Access Memory) is the best known form of memory your computer uses to temporarily store and access data. From the time you turn on your computer, your CPU is constantly using memory (RAM). Every time something is opened or loaded, it gets placed into RAM. This means it is put into a temporary storage area so the CPU can more easily access the information. From there it becomes a continuous cycle where the CPU requests data from RAM, processes it and then writes new data back to RAM. In most computers, this transfer of data between CPU and RAM happens millions of times every second. When an application is closed, the application itself, along with all its accompanying files is deleted from RAM. This is to make sure there is room for new data, so unless the changed files are saved to a permanent storage device, they will be lost.
DIfferent Types of RAM:
RAM Type: Pins: Usage:
SD RAM 168 Typically only used in older and slower computers.
Rambus RAM 184 Only used in certain Pentium 4’s with certain Intel chipsets.
DDR RAM 184 Faster version of SD RAM used in Pentium 4’s and Athlon
DDR2 RAM 240 Newer version of DDR RAM with higher clock frequencies
DDR3 RAM 240 Newer version of DDR2 with higher clock frequencies
When looking to upgrade your computer’s RAM, you will find RAM information typically displayed like this:
1GB, 240-pin DIMM, DDR2 PC2-5300,
* 1GB refers to the size of the memory
* 240-pin refers to the number of pins used to connect to the motherboard
* DIMM- Dual In-line Memory Module
* SIMM- Single In-line Memory Module
* DDR2 refers to the type of memory
* PC2-5300 refers to the module type
Some other pieces of information you might find in a RAM description are:
Clock frequency-refers to speed of the RAM in MHz (800MHz)
CAS (Column Address Strobe) Latency-refers to the number of clock cycles that elapse from the time the request for data is sent to the actual memory location until the data is transmitted from the module. This is represented by a set of 4 numbers also known as RAM timing (4-4-4-12). These numbers stand for:
TCL - CAS Latency Time
Trcd - DRAM RAS# to CAS# Delay
Trp - DRAM RAS# Precharge
Tras - Precharge delay
Normally the BIOS will allow a user to adjust RAM timing to increase performance and stability.
RAM is considered the most critical component in a computer system. Every bit of data must pass through RAM to get to the processor. Generic, low-cost RAM is most often the cause of data corruption and program crashes, so never skimp on the quality of RAM when upgrading RAM. Make sure the RAM you choose is considered Grade A RAM. Grade A RAM can only be found through major manufacturers of RAM, such as: Crucial.com.
DIfferent Types of RAM:
RAM Type: Pins: Usage:
SD RAM 168 Typically only used in older and slower computers.
Rambus RAM 184 Only used in certain Pentium 4’s with certain Intel chipsets.
DDR RAM 184 Faster version of SD RAM used in Pentium 4’s and Athlon
DDR2 RAM 240 Newer version of DDR RAM with higher clock frequencies
DDR3 RAM 240 Newer version of DDR2 with higher clock frequencies
When looking to upgrade your computer’s RAM, you will find RAM information typically displayed like this:
1GB, 240-pin DIMM, DDR2 PC2-5300,
* 1GB refers to the size of the memory
* 240-pin refers to the number of pins used to connect to the motherboard
* DIMM- Dual In-line Memory Module
* SIMM- Single In-line Memory Module
* DDR2 refers to the type of memory
* PC2-5300 refers to the module type
Some other pieces of information you might find in a RAM description are:
Clock frequency-refers to speed of the RAM in MHz (800MHz)
CAS (Column Address Strobe) Latency-refers to the number of clock cycles that elapse from the time the request for data is sent to the actual memory location until the data is transmitted from the module. This is represented by a set of 4 numbers also known as RAM timing (4-4-4-12). These numbers stand for:
TCL - CAS Latency Time
Trcd - DRAM RAS# to CAS# Delay
Trp - DRAM RAS# Precharge
Tras - Precharge delay
Normally the BIOS will allow a user to adjust RAM timing to increase performance and stability.
RAM is considered the most critical component in a computer system. Every bit of data must pass through RAM to get to the processor. Generic, low-cost RAM is most often the cause of data corruption and program crashes, so never skimp on the quality of RAM when upgrading RAM. Make sure the RAM you choose is considered Grade A RAM. Grade A RAM can only be found through major manufacturers of RAM, such as: Crucial.com.
Information about Computer Memory
Computer Memory are internal storage areas in the computer used to either temporarily or permanently store data or instructions to be processed. There are four basic types of computer memory: Cache Memory, RAM, Virtual Memory and Hard Drives. With modern CPU’s running at speeds of 1 gigahertz or higher, it is hard for computer memory to keep up with the extreme amount of data being processed. Computer engineers fixed the problem by "tiering" memory. By using this tiering effect, engineers use a small amount of more expensive memory and a large amount of low cost memory.
RAM:
RAM (Random Access Memory) is the best known form of memory your computer uses. Every file or application opened is placed in RAM. Any information the computer needs or uses becomes part of a continuous cycle where the CPU requests data from RAM, processes it and then writes new data back to RAM. This can happen millions of times a second. However, this is usually just for temporary file storage, so unless the data is saved somewhere, it is deleted when the files or applications are closed.
Hard Drive:
A Hard Drive is a form of computer memory that allows you to permanently store data. This is where all of your permanent files and programs are stored. On computers running with Microsoft windows the Hard Drive is often called C-Drive. The size of a Hard Drive is typically measured in gigabytes.
Virtual Memory:
Virtual memory typically comes into place when applications are too large for the RAM to handle. The operating System uses the hard drive to temporarily store information and take it back when needed. This is normally a lot slower than actual RAM and can possibly degrade performance if used to heavily.
Cache Memory:
Cache Memory is used in-between the CPU and the RAM and holds the most frequently used data or instructions to be processed. There are three different grades of Cache. Some systems will only have level 1 and level 2. More advanced systems will include the level 3.
Level 1 (L1) - Is the primary and is on or very close to the processor. This is used for the most frequently used data and instructions.
Level 2 (L2) - Is second closest to the CPU and is more common to be on the motherboard. Depending on your motherboard it might be able to be updated. This is used for the most frequently used data and instructions.
Level 3 (L3) - This is the most advanced cache and will speed up the memory even further. This is used for the most frequently used data and instructions
RAM:
RAM (Random Access Memory) is the best known form of memory your computer uses. Every file or application opened is placed in RAM. Any information the computer needs or uses becomes part of a continuous cycle where the CPU requests data from RAM, processes it and then writes new data back to RAM. This can happen millions of times a second. However, this is usually just for temporary file storage, so unless the data is saved somewhere, it is deleted when the files or applications are closed.
Hard Drive:
A Hard Drive is a form of computer memory that allows you to permanently store data. This is where all of your permanent files and programs are stored. On computers running with Microsoft windows the Hard Drive is often called C-Drive. The size of a Hard Drive is typically measured in gigabytes.
Virtual Memory:
Virtual memory typically comes into place when applications are too large for the RAM to handle. The operating System uses the hard drive to temporarily store information and take it back when needed. This is normally a lot slower than actual RAM and can possibly degrade performance if used to heavily.
Cache Memory:
Cache Memory is used in-between the CPU and the RAM and holds the most frequently used data or instructions to be processed. There are three different grades of Cache. Some systems will only have level 1 and level 2. More advanced systems will include the level 3.
Level 1 (L1) - Is the primary and is on or very close to the processor. This is used for the most frequently used data and instructions.
Level 2 (L2) - Is second closest to the CPU and is more common to be on the motherboard. Depending on your motherboard it might be able to be updated. This is used for the most frequently used data and instructions.
Level 3 (L3) - This is the most advanced cache and will speed up the memory even further. This is used for the most frequently used data and instructions
Information about Advanced Graphics Port Video Cards
AGP (Advanced Graphics Port) Video Cards are still considered the standard for video cards on the market today. Even though they do not offer all of the features that the PCI Express Video Cards have, they are big step up from PCI Video cards. AGP video cards can be capable of over 4 times the data transfer speed over PCI. AGP improved its data transfer rate by enabling data to be transferred both during the rise and fall of its clock cycle.
AGP uses pipelining and sideband addressing to improve its overall speed. Pipelining is a way to improve performance by letting tasks overlap themselves (For instance: AGP makes multiple requests for information during bus or memory access and PCI makes one request and does not make another until the data has been transferred). Sideband addressing separates the address bus from the data bus, which allows the graphics controller to issue new AGP commands while the main address/data lines are still operating. These two features greatly improve the speed of this style video card.
There are three versions and four basic speeds of AGP Video Cards:
AGP 1.0- supports 1x and 2x speeds and has a 3.3v connector
AGP 2.0- this version is compatible with 1.0 but adds 4x and 1.5v support
APG 3.0-supports 4x and 8x speeds and is only compatible with the 4x version in 2.0
There are three different types of AGP mechanical board connectors. The 3.3v (which usually has a notch at the front end), the 1.5v (which usually has a notch at the back end), and the universal AGP slot which supports multiple voltages (there are no notches so both style cards can fit in it). The AGP card and the monitor are what determine the quality of a computer’s video display, so keep in mind that the newer versions are better for more advanced graphics.
AGP uses pipelining and sideband addressing to improve its overall speed. Pipelining is a way to improve performance by letting tasks overlap themselves (For instance: AGP makes multiple requests for information during bus or memory access and PCI makes one request and does not make another until the data has been transferred). Sideband addressing separates the address bus from the data bus, which allows the graphics controller to issue new AGP commands while the main address/data lines are still operating. These two features greatly improve the speed of this style video card.
There are three versions and four basic speeds of AGP Video Cards:
AGP 1.0- supports 1x and 2x speeds and has a 3.3v connector
AGP 2.0- this version is compatible with 1.0 but adds 4x and 1.5v support
APG 3.0-supports 4x and 8x speeds and is only compatible with the 4x version in 2.0
There are three different types of AGP mechanical board connectors. The 3.3v (which usually has a notch at the front end), the 1.5v (which usually has a notch at the back end), and the universal AGP slot which supports multiple voltages (there are no notches so both style cards can fit in it). The AGP card and the monitor are what determine the quality of a computer’s video display, so keep in mind that the newer versions are better for more advanced graphics.
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