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Which power-saving mode in an OS retains open programs and documents in the RAM but puts the hardware in a low-power state?
Hibernate
Sleep
Shutdown
Restart
Sleep
Sleep mode is a power-saving state that allows a computer to quickly resume full-power operation by keeping the system state, including open programs and files, in the Random Access Memory (RAM). It reduces power consumption by cutting power to non-essential components while maintaining a low-voltage supply to the memory modules.
ACPI Specification, Section 7.3.3 (System Sleep States)
Sleep mode is a power-saving state that allows a computer to quickly resume full-power operation by keeping the system state, including open programs and files, in the Random Access Memory (RAM). It reduces power consumption by cutting power to non-essential components while maintaining a low-voltage supply to the memory modules.
PsleepтАЛтЙИPmemoryтАЛ+PlogicтАЛ
TresumeтАЛтЙкTcold-bootтАЛ
In sleep mode, the OS instructs the ACPI (Advanced Configuration and Power Interface) controller to enter a state (typically S3) where the processor is placed in a low-power mode and most hardware peripherals are turned off. However, the RAM remains powered to prevent the loss of data stored in volatile memory, enabling the system to 'wake' in seconds.
Sleep mode retains data in RAM; Hibernate writes data to the Hard Disk (HDD/SSD).
Uses S3 state in the ACPI power management model.
Quick resume time compared to hibernation or cold boot.
Power interruption during sleep leads to loss of unsaved data.
Near-instant return to work.
Low power consumption compared to 'Active' state.
Vulnerable to power failure causing data loss.
Higher power drain compared to Hibernation.
Laptops and tablets during short idle periods.
Desktops during brief intervals between tasks.
| Feature | Hibernate | Sleep |
|---|---|---|
State Location | Hard Drive (Disk) | RAM (Memory) |
Resume Speed | Slow | Fast |
Hibernate (S4) saves the memory content to the non-volatile storage (disk) and powers off the system completely.
Shutdown (S5) clears the RAM and powers off the hardware completely, requiring a full re-initialization of the OS upon power-up.
Restart involves shutting down the OS and re-booting the entire system kernel.
B is correct тАФ Sleep mode preserves the system state in RAM while keeping hardware in a low-power state for rapid resumption.
Always distinguish between SтВГ (Sleep) and SтВД (Hibernate) states in OS architecture questions; remember that RAM is volatile (PpowerтАЛ>0 required) while Disk is non-volatile.