hardware basic Questions and answers

What’s the maximum hard drive size for FAT16-based Windows system?

The 2-GB partition limit is imposed by the maximum number of clusters and the largest cluster size supported by the FAT file system. The FAT file system is limited to 65,525 clusters. The size of a cluster must be a power of 2 and less than 65,536 bytes--this results in a maximum cluster size of 32,768 bytes (32K). Multiplying the maximum number of clusters (65,525) by the maximum cluster size (32,768) equals 2 GB.

How many hard drives do we generally can accommodate in a pc?

If you have latest motherboard it supports 6 hard disks.

Generally in a system we can connect 4 hard drives that can be through sata (small computer system interface) or IDE (integrated drive electronic)
1.primary master
2.primary slave
3.secondary master
4.secondary slave

Where does CPU Enhanced mode originate from?
Intel’s 80386 was the first 32-bit processor, and since the company had to backward-support the 8086. All the modern Intel-based processors run in the Enhanced mode, capable of switching between Real mode (just like the real 8086) and Protected mode, which is the current mode of operation.

Where does the Real mode on the CPU come from?

The original 8086,which only had 1MB of memory. This megabyte is split into low memory for IRQ tables, application memory and high memory.

How many logical drives is it possible to fit onto a physical disk?

Maximum of 24 logical drives. The extended partition can only have 23 logical drives.

A & B are reserve for floppy disk, C for primary partition for installing o.s., remaining 23 D to Z we can make as logical drives

Name the processor lines of two major manufacturers?

High End Desktop :
Intel - Pentium 4, P4 HT, P4 Extreme Edition with HT, Pentium D, Core 2 Duo, Core 2 Quad, core i5,corei7  etc.
AMD - Athlon XP, Athlon DX, Athlon FX, Athlon 64, Athlon 64 X2, Phenom X3, Phenom X4 etc.
Low End Desktop:
Intel - Celeron, Celeron D.
AMD - Sempron, Sempron X2, 1258 , athlon64,phenomx3etc.
Notebook/Mobile computer :
Intel - Centrino, Centrino 2, Atom etc.
AMD - Turion
Server :
Intel - XEON
AMD – OPTERON

What’s the difference between L1 and L2 cache?

L1 or level 1 is primary cache. Is the fast memory on cpu. It is build in to the processes. it is very small 8kb to 64kb.and it is fast and run as the same speed as the processed.
L2 or level 2 secondary cache is larger and silently slower than L1 cache memory. It is usually 64kb to 2mb in size.

L1 cache is internal to the cpu(inbuilt)
L2 cache is external

What difference between original & chip set motherboard?

Chipset is a motherboard that comprises of the display card, the sound card built-in on the motherboard and the chipsets have each module designed by various manufacturers.
Original motherboard does not comprise of any built in peripherals. They provide supporting chips to enable the peripherals such as an AGP or a VGA card slot for a display card, PCI slot for Sound Card etc...

In motherboard chipset, the chip like North Bridge & south bridge are differing from motherboard manufacturer. In original, the motherboard & chipset all are from same company manufacturer.
E.g. INTEL original & intel chipset.

How do you clear CMOS password?

Since CMOS is a special chip with its own battery, the best way to clear out a CMOS chip is to disconnect it from its power supply.

Remove the CMOS battery for 5 minutes.

Another method to remove CMOS password is by changing jumper form pin 1 , 2 to 2 , 3 and then switch on computer for 20 sec and again change jumper setting to default 1, 2.

What are the basic expansion card types?

ISA and PCI, ISA can be used only on XT, AT and ATX boards. The industry now considers ISA obsolete. ISA - Integrated standard architecture, PCI-peripheral component interface, PCI-eXP-peripheral component interface express, AGP-accelerated graphical port, AMR-audio modem raiser CMR - communication & modem raiser

How does the browser know to go to a certain IP address when you enter a domain like google.com? 

It searches through local DNS cache, if nothing is there, it queries the ISP?s DNS server.

When we type in a domain name into our browser and hit enter, our computer goes and asks another server, called a ?DNS? or ?Domain Name Server? What the IP address is for that domain name. When our computer knows the IP address, it sends off the request and receives that answer back. In this case, the request is for a file that creates the web page in our browser.

How boot sequence process happens?

When the computer's power is first turned on, the CPU initializes itself, which is triggered by a series of clock ticks generated by the system clock. Part of the CPU's initialization is to look to the system's ROM BIOS for its first instruction in the startup program. The ROM BIOS stores the first instruction, which is the instruction to run the power-on self test (POST), in a predetermined memory address. POST begins by checking the BIOS chip and then tests CMOS RAM. If the POST does not detect a battery failure, it then continues to initialize the CPU, checking the inventoried hardware devices (such as the video card), secondary storage devices, such as hard drives and floppy drives, ports and other hardware devices, such as the keyboard and mouse, to ensure they are functioning properly.

What?s the speed and device maximum specs for Firewire?

IEEE 1394 (Firewire) supports the maximum of 63 connected devices with speeds up to 400 Mbps. 

Where?s MBR located on the disk?

Main Boot Record is located in sector 0, track 0, head 0, cylinder 0 of the primary active partition. 

MBR store in primary partition.

WHat are * and ? when using them for wildcards in Windows? * 

Cloud (Or) any characters, arbitrary amoung, ? - single character.

What is TCP/IP?

TCP/IP (Transmission Control Protocol/Internet Protocol) is the basic communication language or protocol of the Internet. It can also be used as a communications protocol in a private network (either an intranet or an extranet). When you are set up with direct access to the Internet, your computer is provided with a copy of the TCP/IP program just as every other computer that you may send messages to or get information from also has a copy of TCP/IP.

Tcp/Ip is a combination of Transimission control protocol and Internet protocol.
An IP address is a 32-bit address broken down into four blocks of 8 bits represented by a decimal number. For example, the dotted-decimal ip address 207.56.10.3 represents the binary number 11001111.00111000.00001010.00000011
Ip is Internet Protocol is used to identify the system on the network and provide communication. and runs on the port no 17.

What is virtual memory? 

Which is not a real memory nothing but RAM

Virtual memory is the use of space on a hard disk drive (HDD) to simulate additional main memory.
Memory is used to hold portions of the operating system, programs and data that are currently in use or that are frequently used. Physically, main memory (also referred to as primary memory) consists of random access memory (RAM) chips that are combined into modules which, in turn, are inserted into slots on the motherboard (i.e., the main circuit board) on a computer. The times required to access different addresses (i.e., locations) in RAM are extremely short and nearly equal, in contrast to the varying delay times for accessing locations on the HDD and other storage devices.

Difference between BETWEEN SRAM and DRAM ? 

 SRAM is used to execute critical code and timer related odes. SRAM doesn't need periodical refreshing since it is made up of flip flops. SRAM consumes less power.
DRAM is used for main application execution. DRAM needs periodical refreshing since it is made up of transistors. Refreshing period may vary depend on vendor normally it is 2ms. DRAM consumes more power than SRAM

What is DTB? 

Dynamic Transaction Back-out. A process to recover recoverable resources based on information stored in the Dynamic Log. 

How do address and data lines are demultiplexed in 8085? 

During the first clock cycle of a memory access, the data lines contain the low order address. External hardware is expected to latch that address on the trailing edge of ALE, Address Latch Enable. During the next clock cycle, the data lines either float (for read, S1=1) or change to data value (for write, S1=0).

In an 8085, the low order address and the data bus share the same pins.
During the first clock cycle of a memory access, the data lines contain the low order address. External hardware is expected to latch that address on the trailing edge of ALE, Address Latch Enable. During the next clock cycle, the data lines either float (for read, S1=1) or change to data value (for write, S1=0).

Which interrupt has the highest priority? 

TRAP has the highest priority

The TRAP is nonmaskable interrupt know as NMI(non-maskable interrupt). It has highest priority among the interrupt signal because,it need not be enabled and can not be disabled.It is level-and edge-sensitive,meaning that the input should go high and stay high to be acknoledged.It can not be acknoledged again until it maks a transition from high to low to high.

What are input & output devices? 

input device- keybord floppy disk cd rom mouse joy stike
out device - printer, scenner, lcd, moniter,

What is Program counter?

Program counter holds the address of either the first byte of the next instruction to be fetched for execution or the address of the next byte of a multi byte instruction, which has not been completely fetched. In both the cases it gets incremented automatically one by one as the instruction bytes get fetched. Also Program register keeps the address of the next instruction.

Program counter is 16 bit register which hold the address of next instruction to be executed.

Difference between memory mapped IO and IO mapped IO? 

Memory mapped IO is one where the processor and the IO device share the same memory location (memory) while IO mapped IO is one where the processor and the IO device have different memory located to each other.

Memory-mapped I/O uses the same address bus to address both memory and I/O devices, and the CPU instructions used are same for accessing the memory and also accessing devices. In order to accommodate the I/O devices, areas of CPU's addressable space must be reserved for I/O.
IN IO mapped IO special class of CPU instructions are used for performing I/O./O devices have a separate address space from general memory, either accomplished by an extra "I/O" pin on the CPU's physical interface, or an entire bus dedicated to I/O.