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A number system's base equals the count of distinct digit symbols it uses before a positional carry occurs. The hexadecimal system uses the symbols 0 to 9 plus A to F, giving sixteen distinct digits, so its radix is 16. This is why each hexadecimal position represents a power of 16.
Each binary digit is multiplied by its positional weight, which doubles from right to left: 1×8 + 1×4 + 0×2 + 1×1. Adding these weighted values gives 8 + 4 + 0 + 1 = 13. The zero in the 2's place contributes nothing, which is why the answer is not 15.
Repeated division by 2 gives remainders 1, 0, 1, 1, 0, 1 reading upwards from the least significant bit, and 32 + 8 + 4 + 1 = 45. Padded to eight bits this is 00101101. Checking the positional weights confirms the sum equals the original decimal value.
Binary is grouped into threes from the right: 101 and 110. The group 101 equals decimal 5 and the group 110 equals decimal 6, so the octal result is 56. Grouping from the right is essential because each octal digit maps to exactly three binary bits.
Split the 8-bit pattern into two nibbles: 1111 and 1010. The nibble 1111 equals decimal 15, written as F, and 1010 equals decimal 10, written as A. Concatenating the two hexadecimal digits in the same left-to-right order gives FA.
Standard ASCII is a 7-bit code, giving 2^7 = 128 distinct character codes covering English letters, digits, punctuation and control characters. Extended ASCII later used 8 bits to add another 128 codes. The syllabus distinguishes the standard 7-bit form from these extensions.
Unicode assigns a unique code point to characters from virtually every script, including Malayalam, Devanagari and Arabic. ASCII and EBCDIC are limited legacy codes tied to English and to specific mainframe families. Unicode is therefore the standard used when multilingual text must be stored consistently.
First write +5 as 00000101. Invert all bits to get 11111010, then add 1 to obtain 11111011. This pattern represents −5 because the leading bit is 1 and the value equals −128 + 64 + 32 + 16 + 8 + 2 + 1.
The AND gate implements logical multiplication, so its output is 1 only when every input is 1; a single LOW input drives the output LOW. The OR gate instead outputs HIGH when any input is HIGH. The NOT gate has only one input and inverts it.
A NAND gate is an AND gate followed by an inverter. With both inputs HIGH the AND output is 1, and inverting it produces 0. Therefore the NAND output is LOW only in the all-ones case.
A gate is called universal when it can implement AND, OR and NOT by itself, and both NAND and NOR satisfy this. NOR is universal because tying both inputs together produces NOT, and combinations of NOR gates reproduce AND and OR. AND, OR and XOR cannot invert a signal alone, so they are not universal.
Applying the distributive and complement laws, A + A'B = (A + A')(A + B). Since A + A' = 1, the expression reduces to A + B. This is a standard simplification step used when minimising combinational logic.
The ALU is the part of the CPU that performs operations such as addition, subtraction, comparison and bitwise logic. It works on operands supplied from registers and returns results to a register. It does not store programs, translate source code, or hold files permanently.
The Program Counter holds the address of the next instruction in the fetch sequence and is incremented after each fetch. The Instruction Register instead holds the instruction currently being decoded and executed. Keeping address and contents in separate registers is what makes the fetch cycle orderly.
Volatility refers to loss of stored content when electrical power is removed, which is characteristic of RAM. Because the main memory is volatile, unsaved work disappears on a power failure. Non-volatile media such as hard disks and ROM keep their contents without power.
Optical discs such as CD, DVD and Blu-ray store data as microscopic pits and lands that are read by a laser beam. Hard disks and magnetic tape use magnetic fields, while flash drives use floating-gate transistors. The reading mechanism is therefore the distinguishing feature.
Each step upward multiplies by 1024, so 4 MB = 4 × 1024 × 1024 bytes. Computing 1024 × 1024 gives 1,048,576, and multiplying by 4 gives 4,194,304 bytes. Using 1000 instead of 1024 would give the decimal approximation rather than the binary value.
System software includes operating systems, device drivers and language translators that manage hardware and provide a platform for other programs. Application software instead performs user-oriented tasks such as word processing. Utility programs are a narrower category of housekeeping tools.
A compiler processes the entire source program and produces a separate object code file before execution, so errors are reported together after compilation. An interpreter translates each statement and executes it immediately, stopping at the first error. This difference explains why compiled programs usually run faster while interpreted ones are easier to debug.
The waterfall model arranges analysis, design, coding, testing and maintenance as a strict sequence, with each phase finished before the next starts. Because requirements are fixed at the beginning, later changes are costly. Iterative models such as spiral and prototyping deliberately revisit earlier stages.
The Arithmetic Logic Unit (ALU) is the part of the CPU that carries out all arithmetic operations and logical comparisons. The control unit only directs and coordinates operations, while memory and input units store and supply data. Hence the ALU is the correct answer.
RAM is the main memory that temporarily holds the instructions and data of programs currently being executed by the CPU. It is volatile, so its contents are lost when power is switched off. Permanent storage is the job of secondary memory such as a hard disk or ROM.
System software manages hardware and provides a platform for running other programs; the operating system is the classic example. Spreadsheets, image editors and browsers are application software written to perform user-level tasks. Therefore only the operating system belongs to the system software category.
The scheduler is the part of the operating system that selects among ready processes and assigns the CPU to one of them according to a scheduling policy. Compilation, disk block allocation and desktop rendering are separate functions. Thus choosing the next process for the CPU is the scheduler's job.
An optical disc drive uses a laser beam to read pits and lands on media such as CD, DVD and Blu-ray discs. Hard disks and tape drives use magnetic recording, while solid state drives use flash memory with no moving optical mechanism. Hence the optical drive is correct.
An optical mark reader senses marks on answer sheets and sends that data into the computer, so it is an input device. Plotters, speakers and monitors all present processed output to the user and are output devices. Therefore the optical mark reader is the only input device listed.
Disk space is allocated in whole blocks, so a 5000-byte file needs the ceiling of 5000 divided by 4096, which is 2 blocks. The first block holds 4096 bytes and the second holds the remaining 904 bytes. Allocation is never done in single bytes, so 5000 is wrong.
The program counter holds the address of the next instruction to be fetched and is incremented during the fetch cycle. The instruction register holds the instruction currently being decoded, the accumulator holds intermediate arithmetic results, and the memory data register buffers data moving to or from memory. Hence the program counter is correct.
Virtual memory extends the usable address space by keeping inactive pages on disk and bringing them into RAM only when they are referenced. This demand paging lets the logical address space exceed physical memory. It does not involve compression, clock speed changes or automatic parallelisation across processors.
Deadlock occurs when a set of processes are each waiting for a resource held by another in the same set, so none can proceed. The circular wait between two processes holding and requesting each other's resources is the classic case. Ordinary I/O waiting, preemption and early completion do not involve such circular blocking.
A GUI presents visual elements such as icons, windows and menus that users manipulate with a mouse or touch, which is easier for beginners. It generally uses more memory and graphics resources than a CLI and never removes the need for the kernel. Execution speed of programs is not determined by the interface type.
A device driver is the software module that translates general operating system requests into commands the specific hardware understands. The boot loader starts the system, the shell interprets user commands, and a file allocation table tracks disk clusters. Therefore the driver is what enables application-to-printer communication.
At power-on the firmware (BIOS/UEFI) performs the power-on self-test, then locates and reads the boot sector, which loads the operating system kernel. Only after the kernel initialises does the system start user programs. The other sequences place steps in impossible orders.
BIOS stands for Basic Input Output System, firmware stored in ROM that initialises hardware and starts the boot process. The other expansions are invented combinations that do not match the standard term. Remembering the words Basic, Input, Output and System fixes the answer.
A cache miss forces the CPU to fetch data from main memory, which is much slower than cache, so execution time increases. Cache memory is volatile and temporary, holding copies of recently used data only. It never rewrites program instructions or raises clock frequency on its own.
A compiler translates the entire source program into machine code or object code before it runs, whereas an interpreter translates and executes statements one at a time. This is why compiled programs usually run faster after translation, while interpreted programs are easier to debug interactively. The other options misstate how each tool works.
With round robin, each process runs for 4 ms in arrival order, so after the first round P1, P2 and P3 each have 2 ms remaining. The second round serves them in the same order, and each finishes when its remaining 2 ms is used. Thus completion follows the original order P1, P2, P3.
A page size of 4 KB equals 2 raised to 12 bytes, so 12 bits are needed to address any byte within a page. These low-order bits form the offset, and the remaining 20 bits identify the page number. Therefore the offset is 12 bits.
SSTF always picks the request closest to the current head position. Distances from track 50 are 32 to track 82, 7 to track 43, 90 to track 140 and 120 to track 170. The smallest distance is 7, so track 43 is served first.
Each process holds one resource and waits for the one held by the other, forming a cycle, so the condition illustrated is circular wait. The standard simple remedy is to impose a total ordering on resource types so requests are always made in increasing order, which makes a cycle impossible. Random termination and blanket denial are not sound general solutions.
The sender (source) is the device that creates and originates the data for transmission in a communication system. The receiver is the destination device, the medium carries the signal, and the protocol is the set of rules. Thus only the sender generates the message.
A Local Area Network covers a limited geographic area such as a building or campus and is privately owned. A MAN spans a city, a WAN spans countries, and a PAN is a personal network around one person. The campus building therefore fits the LAN definition.
Full-duplex mode permits simultaneous two-way transmission because separate channels are available for each direction. Half-duplex allows both directions but only one at a time, and simplex allows only one direction. Broadcast is not a mode classified by direction of flow.
A router operates at the network layer, examines destination IP addresses, and uses a routing table to forward packets between networks. Hubs and repeaters merely regenerate signals, and switches forward frames within a single network segment. Only a router performs inter-network path selection.
In a star topology all nodes connect to a central hub or switch, creating a single point of failure at that centre. Ring and bus topologies do not depend on one central device, and mesh provides redundant paths. Hence the described weakness belongs to the star topology.
Packet switching divides data into small packets that travel independently and may follow different routes before reassembly at the destination. Circuit switching reserves a dedicated path, and message switching stores and forwards whole messages. Frequency switching is not a switching technique.
Attenuation is the loss of signal strength as it propagates over distance through a medium. Distortion is a change in waveform shape, while noise and interference are unwanted signals added from external sources. Only attenuation refers to weakening with distance.
Optical fibre carries data as light pulses through a glass or plastic core, giving very high bandwidth and immunity to electromagnetic interference. Coaxial and twisted pair cables carry electrical signals, and microwave is an unguided medium. The light-based description matches optical fibre.
Unshielded twisted pair is inexpensive, flexible and easy to install, making it the usual choice for short in-building links. Optical fibre is costlier and needs specialised termination, coaxial is bulkier, and satellite is unsuitable for a short indoor link. Hence UTP fits the requirement best.
A modem performs modulation and demodulation, converting digital data to analog form for transmission and back to digital at reception. Storing web pages is a proxy or server function, IP assignment is done by DHCP, and MAC-based segment connection is switching. Only the modem performs signal conversion.