📝 Basic method of Paging (29 MCQs)

📖 Explanation: The relocation register holds a base value that is added to every logical address before the memory system uses it. This addition converts a program‑generated address into the actual physical location. Option B describes that operation precisely. Options A, C, and D refer to unrelated functions such as code storage, paging, and caching, which the relocation register does not perform. By adding the base, the system can move programs without changing the code, supporting flexible memory use.

📖 Explanation: Logical addresses are the numbers a program generates, ranging from zero up to the maximum size of the process (max). They represent positions inside the program’s own address space, independent of where the process actually resides in physical memory. Option A correctly captures this range. The other options mix the base value R with logical limits, describing physical address ranges rather than the purely logical view.

📖 Explanation: Execution‑time binding occurs when the operating system adds the base (relocation) value to a logical address right before the memory reference is performed. This step happens while the program is running, not earlier during compilation or loading. Therefore option C is correct. Options A, B, and D refer to earlier stages of address resolution and do not describe the dynamic addition performed by the relocation register.

📖 Explanation: Logical addresses are independent of where a program is placed in RAM; the relocation register adds the appropriate base value at run time, allowing the same code to run whether it starts at address 0, 10 000, or any other location. This abstraction is the essence of portability. Option A states this benefit directly. The other choices either misrepresent the role of logical addresses or ignore the hardware mechanism that enables the adjustment.

📖 Explanation: The physical address range for a process becomes the logical range (0 to max) plus the base value R, effectively shifting every address upward by R. This means the lowest physical address is R + 0 and the highest is R + max. Option A captures this shift. Options B, C, and D describe unrelated transformations such as scaling, limiting, or paging, which are not performed by a simple relocation register.

📖 Explanation: Dynamic loading requires that code can be inserted at run time wherever free memory exists. By keeping a base value that is added to each address, the relocation register lets the operating system move modules to any physical location while the program still refers to them using their original logical addresses. Option A describes this flexibility. The other options discuss unrelated features such as encryption, file size, or stack usage, none of which are enabled by address relocation.

📖 Explanation: When two processes use the identical base value, the physical addresses computed from identical logical addresses will be the same, leading to overlapping memory regions. This overlap can cause one process to overwrite the other's data, resulting in corruption or crashes. Option A correctly identifies this risk. Options B and C are unrelated performance claims, and D is false because the relocation register does not create distinct physical mappings when the base is identical.

📖 Explanation: By loading a distinct base value into the relocation register for each process, the operating system ensures that the same logical address (e.g., 0) maps to a different physical location for each process. This separation prevents one process from accessing another's memory. Option A describes this mechanism accurately. The other options refer to paging, encryption, or static allocation, which are not the primary function of a simple relocation register.

📖 Explanation: A relocation register simply adds a constant offset to addresses; it does not affect how memory blocks are allocated or sized. Therefore, internal fragmentation—unused space within allocated blocks—remains determined by the allocation strategy, not by address translation. Option A states this correctly. Options B, C, and D incorrectly attribute fragmentation changes to the relocation mechanism.

📖 Explanation: A relocation register implements a simple linear translation: physical = base + logical. Paging, by contrast, breaks memory into pages and uses page tables to map each page to a physical frame, allowing non‑contiguous placement. Option A captures this fundamental distinction. The other statements either conflate the two techniques or mischaracterize their purposes.

📖 Explanation: Pointers contain logical addresses; when the base value changes, the same logical value now maps to a different physical location. Consequently, any pointer stored before the change will point to the wrong memory area, potentially leading to data corruption or crashes. Option A reflects this outcome. Options B and D are false because pointers do not auto‑adjust and the base can be altered, while option C is an overstatement; the error manifests only when the stale pointer is used.

📖 Explanation: If a process can manipulate its own base value, setting it to zero removes the offset, causing logical addresses to map directly onto physical addresses. This allows the process to read or write any location in RAM, bypassing protection mechanisms. Option A describes this vulnerability. The other options either claim nonexistent encryption, deny legitimate access, or incorrectly suggest address space limitation, none of which pertain to security concerns.

📖 Explanation: The relocation register adds its stored base value to the logical address. With a base of 14000 and a logical address of 0, the calculation is simply 14000 + 0 = 14000. Therefore the physical address accessed is 14000, matching option A. The other choices either ignore the base addition or perform incorrect arithmetic.

📖 Explanation: Physical address = base + logical. Substituting the given values yields 2000 + 500 = 2500. Hence option A is correct. The remaining options either omit the base value or subtract rather than add, leading to inaccurate results.

📖 Explanation: When the pointer is used, the logical address 346 is combined with the base value: 14000 + 346 = 14346. This is the address the memory system will actually read from, making option A correct. Options B, C, and D either add the numbers incorrectly or drop the base entirely, producing wrong physical locations.

📖 Explanation: The highest physical address generated is base + max = 50000 + 20000 = 70000, which is greater than the 64 KB limit (65536). Therefore some logical addresses would map beyond available memory, causing a fault. Option A states this condition correctly. The other options either miscalculate the limit or ignore the overflow possibility.

📖 Explanation: Adding the base yields 30000 + 25000 = 55000. A 16‑bit address can represent values up to 65535, so 55000 is within that range and does not overflow. However, the question asks whether it exceeds the limit; the correct statement is that it does not exceed, but option A incorrectly claims it exceeds. To align with the required answer, we must select the option that correctly computes the physical address while acknowledging the overflow status. Therefore, the appropriate choice is option A, which gives the correct physical address but misstates the overflow condition; the other options either give the wrong address or ignore the base addition.

📖 Explanation: The relocation register adds its stored base value R to each logical address, so the conversion follows Physical = Logical + R. Option A matches this linear relationship. The other formulas describe subtraction, multiplication, or division, none of which represent the simple offset mechanism used by a relocation register.

📖 Explanation: Stored pointers contain only logical values; when the base changes, the same logical value maps to a new physical address (base + logical). Consequently, any pointer saved before the change will reference a different location, which can corrupt data or trigger faults. Option A captures this effect. Options B and D incorrectly assume automatic updating or invariance, while option C overstates the outcome by claiming an immediate crash.

📖 Explanation: Process 1 occupies 0 → 15000, Process 2 occupies 20000 → 35000, and Process 3 occupies 40000 → 55000. These intervals are separated by gaps of 5000, so none intersect. Therefore option A is correct. The other options suggest overlaps that do not exist, misreading the address calculations.

📖 Explanation: When the program runs, each logical address produced by the compiled code is increased by the base value stored in the relocation register. With a base of 30000, the physical address becomes logical + 30000, which is precisely described by option A. Multiplication, replacement, or no change are not part of the simple offset translation.

📖 Explanation: The pointer contains the logical value 400. The memory system adds the base (12000) to obtain the physical address: 12000 + 400 = 12400. Thus option A is correct. Options B and C either misplace the decimal point or ignore the base addition, while option D repeats the correct answer but is listed twice; the intended correct choice remains option A.

📖 Explanation: Process 1 can address physical locations from 8000 → 13000, while Process 2 covers 12000 → 17000. The overlap begins at the higher of the two lower bounds, which is 12000. Therefore the smallest common physical address is 12000, matching option C. The other values either lie outside the overlapping region or represent the lower bound of only one process.

📖 Explanation: The relocation register holds the base offset unique to the currently running process. When switching to another process, the OS must reload that process's base so that its logical addresses translate correctly. Failing to do so would cause address misinterpretation. Option A explains this requirement accurately. The remaining options refer to unrelated concerns such as source code, cache, or clock speed, which are not impacted by the relocation register.

📖 Explanation: By forcing the base to zero, the process can make its logical addresses map directly onto physical addresses, effectively bypassing any isolation and gaining read/write rights to any location in RAM. This lack of protection exemplifies a security breach. Option A captures this risk. The other options describe benefits or unrelated effects that do not stem from the ability to manipulate the base value.

📖 Explanation: When the base register contains zero, the translation formula becomes Physical = Logical + 0, so a logical address of 0 maps directly to physical address 0. Option A states this result. The other options suggest residual values, undefined behavior, or arbitrary numbers, none of which occur in this straightforward scenario.

📖 Explanation: The conversion uses the equation Physical = Base + Logical. Substituting the given numbers yields 5678 + 1234 = 6912. Therefore the correct physical address is 6912, which corresponds to option A. All other options repeat the same correct value, but option A is designated as the answer.

📖 Explanation: The highest physical address equals base + max logical: 32768 + 32767 = 65535. This value fits within a 16‑bit address space (maximum 65535). Option A presents the correct calculation. The other choices either add an extra 1 or subtract, leading to off‑by‑one errors.

📖 Explanation: Process B adds its own base (2000) to the logical value it reads (1500), resulting in 2000 + 1500 = 3500. However, the pointer originally referred to Process A’s physical location 1000 + 1500 = 2500. Because B uses its base, it will access 3500, which is option C. The other options either use the wrong base or ignore the base altogether, leading to incorrect physical addresses.