- Chales Babbage is called as the Father of Computers. In 1812 Charles Babbage invented a automatic mechanical calculation device called Difference Engine. Later he designed Analytical Engine which has internal storage for data.
- Use of Windows can be done on 386-AT and above machines.
- Task switching is done by generating internal interrupts.
- Buffers are used to allocate space in memory reserved for file and data transfer.
- What is the order of execution for the startup files? Config.sys then Autoexec.bat
- The ATTRIB command is used to change or display a file attributes.
- Hard drives permit the users accounts to share many programs and documents at same time.
- The command that would be placed in a CONFIG.SYS file – DEVICE=C:DOSHIMEM.SYS
- A flashing “X” means the system cannot find either the system files or finder files.
- Formatting a hard disk erases any previous data store, and it writes the sector ID fields and other information necessary for synchronization.
- The main advantage of raster scan over vector scan is the electronic circuit required for vector scanning is complex and costly.
- If you had a monitor which displayed 640 x 480 in 16 colors, you would have VGA graphics driver.
- The main advantage of giving phosphorous coating to monitor screen is persistence.
- The vertical sync rate is always slower than the horizontal sync rate in monitors.
- The most popular protocol used in Internet the TCP/IP stands for ‘Transmission Control Protocol / Internet Protocol’
- As a network administrator, you have configured the workstations to run TCP/IP. In order to make IP address management easier, you would implement DHCP to allow TCP/IP clients to automatically receive configuration parameters.
- The TCP/IP protocol ‘Telnet’ is a simple remote terminal emulation application, allowing one host to connect to and run a session on another.
- RJ-11 modular connectors are used in Token Ring.
- The main difference between sag and a brownout is sag typically is less than few milliseconds and a brownout lasts for a prolonged period.
- The purpose of shadowing is to copy instructions in ROM to RAM for faster execution.
- The region of RAM containing the same software as ROM is called Shadow RAM.
- SRAM is faster than DRAM. Static RAM is different from Dynamic RAM as Static RAM chips do not require refresh signal to maintain their electrical state.
- A keyboard uses IC 8048 microcontroller
- To add mouse driver for Microsoft Mouse to the CONFIG.SYS file, the command syntax used is DEVICE=C:MOUSEMOUSE.SYS
- In a keyboard, the 20 millisecond wait period for ensuring the key depress is called as Debouncing time.
- The feedback voltage to the PWM section of an SMPS is +5V
- A power surge may have occurred when the light in the room flickers and the computer suddenly reboots by itself.
- When replacing a Switch Mode Power Supply (SMPS) you mush observe Wattage.
- The voltage levels of SMPS used by an FDD are +5V & +12V
- The output of PWM section of an SMPS is driven by Driver Transistors, Driver Transformer (in order).
- Parallel Data Communication follows the Centronics Standard.
- Data is transmitted from the parallel port in the following manner: One byte is transmitted simultaneously as eight bits. One bit is sent on each wire.
- A full duplex modem allows transmitting and receiving data simultaneously.
- A dot matrix printer actually prints on paper using Pins.
- The photosensitive drum in a laser printer is exposed to laser light for the reason that the organic coating on the drum loses it ability to hold the electrical charge when exposed to light.
- The main disadvantage of thermal printers is the requirement of special head sensitive paper.
- SET parameters are available to increase the number of directory cache buffers.
- The newest and most popular type of printer interface is USB
- In a Laser printer, toner is transferred to the print media by Corona Wire.
- The system interrupts used by parallel ports are IRQ 5, IRQ 7
- Here’s the list of IRQ numbers along with their functions and availability status for change
| IRQ Numbers | Function | Available for Change |
|---|---|---|
| 0 | System Timer | No |
| 1 | Keyboard | No |
| 2 / 9 | Open Interrupt | Yes available |
| 3 | Com2 – Com4 | usually |
| 4 | Com1 – Com3 | usually |
| 5 | LPT2 | usually |
| 6 | FDD | No |
| 7 | LPT1 | usually |
| 8 | Real Time Clock | No |
| 10 | Open Interrupt | Yes |
| 11 | SCSI | Yes |
| 12 | PS/2 mouse | Yes |
| 13 | Math Coprocessor | No |
| 14 | Primary HDD | No |
| 15 | Secondary HDD | No |
- The second most popular Hard disk interface used in PC’s today is Small Computer System Interface (SCSI). It will support many different types of devices.
If has 50 pins -> (8 devices), Untra SCSI has 68 pins (16 devices) and Wide SCSI has 80 pins (16 devices). - Cache memory will do prefetch function. In older days we had internal and external cache. Internal works fast with processor speed and external which stores latest results is slow compared to internal because it works at speed of motherboard. Now there’s L1 and L2 cache working with microprocessor speed. L1 prefetches instructions and L2 cache stores results.
- Present in processor nowadays two techniques:
- If RAM to Cache to Processor then result to RAM it is called Write-Through Cache Technique. This is fast
- If RAM to Cache to Processor then result back in same direction it is called Write-Back Cache Technique. This is slow.
- Based on insertion, PC processors are of two types namely – Low Insertion Force (LIF) and Zero Insertion Force (ZIF) processors.
- On every floppy disk concentrate circles are logically drawn which are called tracks. These tracks are inturn logically divided into pie-slice shaped areas called sectors. 3 1/2″ floppy diskette capacity is 1.44MB and 5 1/4″ floppy diskette capacity is 1.2MB.
- Floppy Diskettes or Floppies are made of plastic material and are coated with magnetic oxide and they are used to store data and information.
- Based on capacity of storage different types of DVDs are:
- DVD-5 discs are single-sided, single-layer recording DVDs with a maximum storage space of 4.7GB
- DVD-9 discs are single-sided, dual-layer recording DVDs with a maximum storage space of 8.5GB
- DVD-10 discs are dual-sided, single-layer recording DVDs with a maximum storage space of 9.4GB
- DVD-18 discs are dual-sided, dual-layer recording DVDs with maximum capacity of 17.1GB Read More on DVD Capacities
- The first step of POST is reset the CPU and program counter F0000
- EISA has 32 bit bus architecture.
- PCI bus architecture supports Plug-and-Play technology.
- MODEM does MOdulations & DEModulation. Modulation is analog to digital and Demodulation is digital to analog.
- Designing of tracks or buses on motherboard is called fabrication. Buses or tracks is protected by -ve image. Motherboards come in different colors like Greenish board (Glass Fible + Epoxy Plastic), Brownish Board (Glass Fibre + Phenolic Plastic) etc. After fabrication board is called PCB (Printed Circuit Board).
- Component insertion on motherboard is of two types:
1. Pin-in-hole or Through-hole technology (older)
2. Surface Mount Technology (New) - Types of Motherboard: IBM approach motherboards used nowadays which is a combination of Bus Based M.B and Single Board Based Motherboards. Before IBM (International Business Machine) approach, there were two types of motherboards used – 1. Bus based motherboard In Bus based motherboards transfer of data is long path and is only through bus. There are only expansion slots so all cards we have to buy. It is slow and costly but has it advantages like upgrade and replacement when faulty.
2. Single Board based motherboard It has integrated chips and devices. Its advantages are low cost and fast. Disadvantages are no upgrade and no component level replacement. - Computer BUS standards:
ISA (Industry Standard Architecture)
MCA (Micro Channel Architecture)
EISA (Extended Industry Standard Architecture)
VESA (Video Electronics Standards Association)
PCI (Peripheral Component Interconnect) - Hard disk is the mass storage device and permanent storage device. For 1 inch it has 1500 tracks. Generally we use 3.5 inches tracks. Per track there are 63 sectors. Per sector 512 bytes of data can be stored.
- To assign addresses or address locations we have to format a hard drive. By formatting, file system forms – FAT16, FAT32, NTFS.
- Data on hard disk is stored in form of cylinder. File system is stored at edge. Read/Write head first searches for a particular file information in file system then goes to particular cylinder where data is present.
- Hard disk partitioning is divided into Primary partition and Extended partition. MBR (Master Boot Record) stores partitioning identification space. At max 4 primary partitions can be made and the limit for extended partitions is 64.
- Hard-disk physical components are as follows: Platter, Spindle, Spindle Motor, Actuator, Actuator Axis, Actuator Arms, Case Mounting Holes, Power Connector, Jumpers, Data Connector, Buffer Chip, Ribbon Cable (Connects Data Connector and Buffer Chip) and IDE Connector.
- The color of the light source on a black & white or grayscale scanner is an important consideration when buying a new scanner.
- In CD-ROM the spindle motor speed varies between 210-539 rpm and this is in order to make more amount of information on the outer area of the CD. This is called Constant Liner Velocity (CLV) technique.
- The CD-RW (Compact Disc-ReWritable) disks are based on phase change technology. The phase change element is chemical compound of Silver (Ag), Antimony (Sb), Tellurium (Te) and Indium (In). When this compound is heated above its melting temperature (600°C) it becomes a liquid. At its crystallization temperature around 200°C it turns into solid.
- In IDE/ATAPI connection, IDE (Integrated Drive Electronics) is the physical interface and ATAPI (Advanced Technology Attachment Packet Interface) is logical interface.
- After installing a scanner and an expansion card on a 16 bit machine the IRQ 10 is most likely to be available.
- The SCSI port interfaces is best suited for receiving input form a scanner.
- Parallel Ports are used to connect host of popular computer peripherals like printer, scanner, external HDD, ZIP drives, network adapters etc.
- The standard length of printer parallel port is max of 15 feet.
- Parallel Port types:
► Unidirectional port doesn’t have the capability of transferring data both ways which means the data transfers only in one direction. This is 4-bit standard port.► First designed by IBM in 1987, the Bidirectional port is 8-bit standard port and sends 8-bit data i/p and o/p. This mode is commonly known as SPP (Standard Parallel Port). Bus speed is 150KB/sec.
► Enhanced Parallel Port (EPP) was released by Intel, Zenith & Xircom in 1991. Bus speed is 1-2MB/sec.► In 1992 Microsoft & Hewlett-Packard jointly announced a specification called Extended Capability Port (ECP). Here first time introduced option of using DMA and buffers.
► In 1994 IEEE 1284 standard was released. It includes both specifications for parallel port devices – ECP + EPP - The number of address bits of 80286 microprocessor are 24.
- Pentium is built on Superscalar CISC architecture.
- “Bad command or file name” error message is given by the system due to DOS not recognizing the command you entered at the DOS command prompt.
- Invalid Partition table is an error message which is stored in MBR.
- FAT and root directory is a team in locating files and sub directories.
- Buffers are used to allocate space in memory reserved for file and data transfer.
- Boot record is present in – side 0, track 0, sector 1
- You have been asked to make a fault tolerance recommendation for your organization. The server stores mission-critical data, spanning four disks. Based on this information, the RAID level you would recommend is RAID level 5.
- Term used to describe time it takes the monitor to paint a picture from top to bottom is Refresh rate.
- An SVGA monitor has more bandwidth than VGA
- The main difference between computer monitor and a TV is that a TV has a receiver and a tuning circuit and monitor has better resolution.
- HTTP the framework for exchanging information on the Word Wide Web stands for Hyper Text Transfer Protocol.
- Repeaters is needed to extend a 10Base2 network beyond the maximum segment distance.
- A device that operates at the OSI Network layer is Router.
- The difference between a transient and sag is that a transient is an overvoltage condition and a sag is an under voltage condition.
- The synchronous burst SRAM is faster than asynchronous burst SRAM.
- The main disadvantage of a mechanical switch in a keyboard is wear and tear.
- An optical-mechanical mouse works on the following principle: Mechanically driven plastic disks break beams of light generating pulses that may be controlled.
- The power supply requirement for a keyboard is +5 volts supply through connector.
- Null Modems transmit data in the following way: Connecting serial ports with a crossed wire cable.
- The factors that affect the speed of a Modem are Version of the UART chip and Data Compression.
- When ink is slightly abrasive and the nozzles are worn when the cartridge runs out of ink you should replace the ink cartridge in an ink-jet printer with a new one.
- In a Laser Printer, the fuser assembly performs the following functions: Melts toner particles and presses them into the Print media.
- The REGISTER MEMORY command enables the operating system to address installed memory greater than 16MB.
- Primary DOS partition cannot be deleted without first deleting the logical drives.
- General failure is given if the DOS has discovered a RAM error while processing.
- You have an internal SCSI Hard Drive as well as an external SCSI Hard Drive, then you put the terminators one at the end of each hard drive and NOT one of the controller.
- Servo board on FDD controls the constant spinning of spindle motor.
- The format procedure establishes the sector interleave factor.
- A picture on a computer monitor is encrypted by a cathode ray scanning across fluorescent screen.
- The grid voltages required for the CRT are obtained from LOT (Line Output Transformer).
- The most popular network management protocol available in the TCP/IP protocol suite is SNMP
- NetBEUI, TCP/IP, Apple Talk are some of the transport-layer or higher-layer protocols.
- The cable type that is least susceptible to EMI interference is Fiber Optic.
- HTTP provides the framework for exchanging of Text, Images, Sound & Video.
- Memory allows the microprocessor to process its program instructions and also its data.
- The biggest difference between EDO RAM and Fast Page Mode RAM is that EDO RAM is faster than Fast Page Mode RAM.
- Synchronous transmission is best described by regular transmission times without start and stop bits.
- The main function of ROM chips is to give the system instructions during start-up.
- The working frequency of SMPS lies in the range of 20KHz to 22KHz
- For computers not protected by UPS, the main problem that can occur when power is restored after a power failure is the damage from a power surge.
- The voltage across the main filtering capacitor (across bridge rectifier) in an SMPS is 300V DC.
- NPRINT loads a printable file directory into a selected print queue.
- A toner cartridge contains the following: Drum, charging roller, developing roller, and a scraper blade.
- Here is how ink is expelled from the ink cartridge in ink-jet printers: A small heating element heats the ink, making steam that forces the ink through a nozzle and a piezo-electric crystal is subjected to an electrical current causing it to bend and push ink through the nozzle.
- Here is how the Printwire in a Dot Matrix Printer fired: An electromagnet is activated forcing the printwire from a permanent magnet in the printhead.
- The first step of a DOS client installation is to select a network board driver.
- Which head placing mechanism places head exactly over the track? => Voice coil mechanism.
- Any absence of characters on the screen of a monitor may denote failure in video section.
- Difference between a surge and a spike is that a spike is a very short over-voltage condition measured in nanoseconds and a surge is measured in milliseconds.
- The process of finding out which key is pressed in keyboard is called Scanning.
- Misaligned platen is most likely the cause of a printer problem that causes printing to become dull from left to right.
- In a Laser Printer, toner is moved to the print media with Transfer/Corona roller.
- Dot matrix impact printers commonly has the following print head pin configuration: 9, 18, 24.