Dweller viruses :
Resident viruses contain a replication module that is similar to the one that is employed by nonresident viruses. This module, however, is not called by a finder module. The virus loads the imitation module into memory when it is executed instead and ensures that this module is executed each time the operating system is called to make a certain operation. The reproduction module can be called, for example, each time the operating system executes a file. In this case the virus infects every suitable program that is executed on the computer.
Resident viruses are sometimes subdivided into a kind of fast infectors and a category of slow infectors. Fast infectors are considered to infect as many files as possible. A fast infector, for instance, canister infects every potential host file that is accessed. This poses a special problem when using anti-virus software, since a virus scanner will access every potential host file on a computer when it performs a system-wide scan. If the virus scanner fails to notice that such a virus is present in memory the virus can "piggy-back" on the virus scanner and in this way infect all files that are scanned. Fast infectors rely on their fast infection rate to spread. The disadvantage of this method is that infecting many files may make detection more likely, because the virus may slow down a computer or perform many suspicious actions that can be noticed by anti-virus software. Slow infectors, on the other hand, are designed to infect hosts infrequently. Some slow infectors, for instance, only infect files when they are copied. Slow infectors are designed to avoid detection by limiting their actions: they are less likely to slow down a computer noticeably and will, at most, infrequently trigger anti-virus software that detects suspicious behavior by programs. The slow infector approach, however, does not seem very successful
Monday, January 25, 2010
Computer Virus
A computer virus is a computer plan that can copy itself and infect a computer. The term "virus" is also frequently but speciously used to refer to other types of malware, adware, and detective ware programs that do not have the reproductive ability. A true virus can only spread from one computer to another
when its host is taken to the target computer; for instance because a user sent it over a network or the Internet, or carried it on a removable medium such as a floppy disk, CD, DVD, or USB drive. Viruses can increase their chances of spreading to other computers by infecting files on a network file system or a file system that is accessed by another computer.
The term "computer virus" is sometimes used as a catch-all phrase to include all types of malware, adware, and spyware programs that do not have the reproductive ability. Malware includes computer viruses, worms, trojans, most rootkits, spyware, dishonest adware, crimeware, and other malicious and unwanted software, including true viruses. Viruses are sometimes confused with computer worms and Trojan horses, which are technically different. A worm can exploit security vulnerabilities to spread itself to other computers without needing to be transferred as part of a host, and a Trojan horse is a program that appears harmless but has a hidden agenda. Worms and Trojans, like viruses, may cause harm to either a computer system's hosted data, functional performance, or networking throughput, when they are executed. Some viruses and other malware have symptoms noticeable to the computer user, but many are surreptitious or go unnoticed.
when its host is taken to the target computer; for instance because a user sent it over a network or the Internet, or carried it on a removable medium such as a floppy disk, CD, DVD, or USB drive. Viruses can increase their chances of spreading to other computers by infecting files on a network file system or a file system that is accessed by another computer.
The term "computer virus" is sometimes used as a catch-all phrase to include all types of malware, adware, and spyware programs that do not have the reproductive ability. Malware includes computer viruses, worms, trojans, most rootkits, spyware, dishonest adware, crimeware, and other malicious and unwanted software, including true viruses. Viruses are sometimes confused with computer worms and Trojan horses, which are technically different. A worm can exploit security vulnerabilities to spread itself to other computers without needing to be transferred as part of a host, and a Trojan horse is a program that appears harmless but has a hidden agenda. Worms and Trojans, like viruses, may cause harm to either a computer system's hosted data, functional performance, or networking throughput, when they are executed. Some viruses and other malware have symptoms noticeable to the computer user, but many are surreptitious or go unnoticed.
Friday, January 8, 2010
Hardware innovtive
Hardware of a modern Personal Computer:
1. Monitor
2. Motherboard
3. CPU
4. RAM Memory
5. Expansion card
6. Power supply
7. Optical disc drive
8. Hard Disk
9. Keyboard
10. Mouse
1. Monitor
2. Motherboard
3. CPU
4. RAM Memory
5. Expansion card
6. Power supply
7. Optical disc drive
8. Hard Disk
9. Keyboard
10. Mouse
Inside a custom computer:
The motherboard is the main component indoors the case. It is a large rectangular board with integrated circuitry that connect the rest of the parts of the computer including the CPU, the RAM, the disk drives as well as any peripherals connected via the ports or the expansion slots. Computer Hardware course is very main in future being b'coz every work done by computer.
Components directly attached to the motherboard include:
The central processing unit (CPU) performs most of the calculations which enable a computer to function, and is sometimes referred to as the "brain" of the computer. It is usually cooled by a heat sink and fan.
The chip set mediates communication between the CPU and the other components of the system, including main memory.
RAM Stores all running processes (applications) and the current running OS. RAM Stands for Random Access Memory
The BIOS includes boot firmware and power management. The Basic Input Output System tasks are handled by operating system drivers.
Internal Buses connect the CPU to various internal components and to expansion cards for graphics and sound.
Current
The north bridge memory controller, for RAM and PCI Express
PCI Express, for expansion cards such as graphics and physics processors, and high-end network interfaces
PCI, for other expansion cards
SATA, for disk drives
Obsolete
ATA (superseded by SATA)
AGP (superseded by PCI Express)
VLB VESA Local Bus (superseded by AGP)
ISA (expansion card slot format obsolete in PCs, but still used in industrial computers)
External Bus Controllers
support ports for external peripherals. These ports may be controlled directly by the south bridge I/O controller or based on expansion cards attached to the motherboard through the PCI bus.
USB
FireWire
eSATA
SCSI
Power supply
A power supply unit (PSU) is the section that supplies influence to the other components in a computer. More specifically, a power supply unit is typically considered to convert general-purpose alternating current (AC) electric power from the mains (100-127V in North America, parts of South America, Japan, and Taiwan; 220-240V in most of the rest of the world) to usable low-voltage DC power for the internal components of the computer. Some power supplies have a switch to change between 230 V and 115 V. Other models have automatic sensors that switch input energy automatically, or are able to accept any voltage between those limits.
The motherboard is the main component indoors the case. It is a large rectangular board with integrated circuitry that connect the rest of the parts of the computer including the CPU, the RAM, the disk drives as well as any peripherals connected via the ports or the expansion slots. Computer Hardware course is very main in future being b'coz every work done by computer.
Components directly attached to the motherboard include:
The central processing unit (CPU) performs most of the calculations which enable a computer to function, and is sometimes referred to as the "brain" of the computer. It is usually cooled by a heat sink and fan.
The chip set mediates communication between the CPU and the other components of the system, including main memory.
RAM Stores all running processes (applications) and the current running OS. RAM Stands for Random Access Memory
The BIOS includes boot firmware and power management. The Basic Input Output System tasks are handled by operating system drivers.
Internal Buses connect the CPU to various internal components and to expansion cards for graphics and sound.
Current
The north bridge memory controller, for RAM and PCI Express
PCI Express, for expansion cards such as graphics and physics processors, and high-end network interfaces
PCI, for other expansion cards
SATA, for disk drives
Obsolete
ATA (superseded by SATA)
AGP (superseded by PCI Express)
VLB VESA Local Bus (superseded by AGP)
ISA (expansion card slot format obsolete in PCs, but still used in industrial computers)
External Bus Controllers
support ports for external peripherals. These ports may be controlled directly by the south bridge I/O controller or based on expansion cards attached to the motherboard through the PCI bus.
USB
FireWire
eSATA
SCSI
Power supply
A power supply unit (PSU) is the section that supplies influence to the other components in a computer. More specifically, a power supply unit is typically considered to convert general-purpose alternating current (AC) electric power from the mains (100-127V in North America, parts of South America, Japan, and Taiwan; 220-240V in most of the rest of the world) to usable low-voltage DC power for the internal components of the computer. Some power supplies have a switch to change between 230 V and 115 V. Other models have automatic sensors that switch input energy automatically, or are able to accept any voltage between those limits.
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