- What are the main differences between Apache 1.x and 2.x?
- What does the “route” command do?
- What are the read/write/execute bits on a directory mean?
- What does iostat do?
- what does vmstat do?
- What does netstat do?
- What is the most graceful way to bring a system into single user mode?
- How do you determine disk usage?
- What is AWK?
- What is SED?
- What is the difference between binaries in /bin, and /usr/bin?
- What is a dynamically linked file?
- What is a statically linked file?
Networking and Unix Interview Questions & Answers
What is UTP?
UTP — Unshielded twisted pair 10BASE-T is the preferred Ethernet medium of the 90s. It is based on a star topology and provides a number of advantages over coaxial media:
It uses inexpensive, readily available copper phone wire. UTP wire is much easier to install and debug than coax. UTP uses RG-45 connectors, which are cheap and reliable.
What is a router? What is a gateway?
Routers are machines that direct a packet through the maze of networks that stand between its source and destination. Normally a router is used for internal networks while a gateway acts a door for the packet to reach the ‘outside’ of the internal network
What is Semaphore? What is deadlock?
Semaphore is a synchronization tool to solve critical-section problem, can be used to control access to the critical section for a process or thread. The main disadvantage (same of mutual-exclusion) is require busy waiting. It will create problems in a multiprogramming system, where a single CPU is shared among many processes.
Busy waiting wastes CPU cycles.
Deadlock is a situation when two or more processes are waiting indefinitely for an event that can be caused by only one of the waiting processes. The implementation of a semaphore with a waiting queue may result in this situation.
What is Virtual Memory?
Virtual memory is a technique that allows the execution of processes that may not be completely in memory. A separation of user logical memory from physical memory allows an extremely large virtual memory to be provided for programmers when only a smaller physical memory is available. It is commonly implemented by demand paging. A demand paging system is similar to a paging system with swapping. Processes reside on secondary memory (which is usually a disk). When we want to execute a process, we swap it into memory.
Explain the layered aspect of a UNIX system. What are the layers? What does it mean to say they are layers?
A UNIX system has essentially three main layers:
. The hardware
. The operating system kernel
. The user-level programs
The kernel hides the system’s hardware underneath an abstract, high-level programming interface. It is responsible for implementing many of the facilities that users and user-level programs take for granted.
The kernel assembles all of the following UNIX concepts from lower-level hardware features:
. Processes (time-sharing, protected address space)
. Signals and semaphores
. Virtual Memory (swapping, paging, and mapping)
. The filesystem (files, directories, namespace)
. Pipes and network connections (inter-process communication)
What is UTP?
UTP — Unshielded twisted pair 10BASE-T is the preferred Ethernet medium of the 90s. It is based on a star topology and provides a number of advantages over coaxial media:
It uses inexpensive, readily available copper phone wire. UTP wire is much easier to install and debug than coax. UTP uses RG-45 connectors, which are cheap and reliable.
What is a router? What is a gateway?
Routers are machines that direct a packet through the maze of networks that stand between its source and destination. Normally a router is used for internal networks while a gateway acts a door for the packet to reach the ‘outside’ of the internal network
What is Semaphore? What is deadlock?
Semaphore is a synchronization tool to solve critical-section problem, can be used to control access to the critical section for a process or thread. The main disadvantage (same of mutual-exclusion) is require busy waiting. It will create problems in a multiprogramming system, where a single CPU is shared among many processes.
Busy waiting wastes CPU cycles.
Deadlock is a situation when two or more processes are waiting indefinitely for an event that can be caused by only one of the waiting processes. The implementation of a semaphore with a waiting queue may result in this situation.
What is Virtual Memory?
Virtual memory is a technique that allows the execution of processes that may not be completely in memory. A separation of user logical memory from physical memory allows an extremely large virtual memory to be provided for programmers when only a smaller physical memory is available. It is commonly implemented by demand paging. A demand paging system is similar to a paging system with swapping. Processes reside on secondary memory (which is usually a disk). When we want to execute a process, we swap it into memory.
Explain the layered aspect of a UNIX system. What are the layers? What does it mean to say they are layers?
A UNIX system has essentially three main layers:
. The hardware
. The operating system kernel
. The user-level programs
The kernel hides the system’s hardware underneath an abstract, high-level programming interface. It is responsible for implementing many of the facilities that users and user-level programs take for granted.
The kernel assembles all of the following UNIX concepts from lower-level hardware features:
. Processes (time-sharing, protected address space)
. Signals and semaphores
. Virtual Memory (swapping, paging, and mapping)
. The filesystem (files, directories, namespace)
. Pipes and network connections (inter-process communication)
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