Menene bambanci tsakanin process da thread?

Question

IT Interview Practice · Accepted Answer

**Process** shiri ne mai gudana da nasa memory keɓaɓɓe (address space); **thread** kuwa naúrar zartarwa ce *a cikin* process. Process guda na iya riƙe threads da yawa, kuma waɗannan threads suna **raba** memory ɗin process — amma kowane process yana keɓe da kowane ɗaya.

## Abin da kowanne ke mallaka

```text
PROCESS A                          PROCESS B
┌─────────────────────────────┐    ┌───────────────┐
│ address space (code/heap)   │    │ address space │
│ file descriptors, PID       │    │  (isolated)   │
│ ┌────────┐ ┌────────┐       │    │  ┌────────┐   │
│ │thread 1│ │thread 2│  ...  │    │  │thread 1│   │
│ │ stack  │ │ stack  │       │    │  │ stack  │   │
│ │ regs/PC│ │ regs/PC│       │    │  └────────┘   │
│ └────────┘ └────────┘       │    └───────────────┘
│  ▲ shared heap, globals, fds│
└─────────────────────────────┘
```

- **Ga kowane process:** address space, buɗaɗɗun file descriptors, PID — keɓaɓɓe gaba ɗaya ta kernel.
- **Ga kowane thread:** nasa **stack**, registers, da program counter (PC).
- **Ana rabawa tsakanin threads a cikin process:** heap, global variables, da buɗaɗɗun files.

## Ciniki mai amfani (trade-off)

- **Threads** suna da arha wajen ƙirƙira kuma suna sadarwa nan take (shared memory) — amma bug a cikin thread ɗaya (mummunan pointer, crash) yana kashe dukkan process, kuma bayanan da ake rabawa suna bukatar locks.
- **Processes** sun fi nauyi kuma dole su yi amfani da IPC don magana, amma keɓewa na nufin process ɗaya da ya crash ba zai lalata wani ba — samfurin da browsers ke amfani da shi don sandbox ɗin tabs.

Context-switching **tsakanin threads** na process ɗaya ya fi arha fiye da tsakanin processes, saboda memory map (da TLB entries ɗinsa) ba sai ya canza ba.

## Me ya sa yake da muhimmanci

"Process vs thread" na ɗaya daga cikin tambayoyin hira na OS da suka fi zama ruwan dare domin amsar tana jagorantar zaɓin ƙira na gaske: threads don shared-memory parallelism a cikin sabis, processes daban-daban don keɓe kuskure (fault isolation) da tsaro sandboxing. Sanin ainihin abin da ake rabawa (heap, fds) da abin da yake na kai (stack, registers) shi ma shi ne tushen fahimtar race conditions da dalilin da ya sa ake bukatar synchronization.

Abin da kowanne ke mallaka

Ciniki mai amfani (trade-off)

Me ya sa yake da muhimmanci

Tambayoyi masu alaƙa