Technical Questions

Object Repository means not a collection of objects

it's a common repository for all the people (testing, developers) for seeing all the data in single login.

for example QA wants to see 5 testers works then he goes  to each person login and see the data. It's very difficult job. for this we can use Object Repository.

EOF has been defined as #define EOF -1 n the file "stdio.h" and an unsigned char ranges from 0 to 255 hence when EOF is read from the file it cannot be accommodated in ch. Solution is to declare ch as an int.

When a program forks and the child finishes before the parent, the kernel still keeps some of its information about the child in case the parent might need it – for example, the parent may need to check the child’s exit status. To be able to get this information, the parent calls `wait()’; In the interval between the child terminating and the parent calling `wait()’, the child is said to be a `zombie’ (If you do `ps’, the child will have a `Z’ in its status field to indicate this.)

It is a useful, memory-saving technique for multiprogrammed timesharing systems. A Reentrant Procedure is one in which multiple users can share a single copy of a program during the same period. Reentrancy has 2 key aspects: The program code cannot modify itself, and the local data for each user process must be stored separately. Thus, the permanent part is the code, and the temporary part is the pointer back to the calling program and local variables used by that program. Each execution instance is called activation. It executes the code in the permanent part, but has its own copy of local variables/parameters. The temporary part associated with each activation is the activation record. Generally, the activation record is kept on the stack.

Note: A reentrant procedure can be interrupted and called by an interrupting program, and still execute correctly on returning to the procedure.

A view may be a subset of the database or it may contain virtual data that is derived from the database files but is not explicitly stored .

Preemptive scheduling: The preemptive scheduling is prioritized. The highest priority process should always be the process that is currently utilized.

Non-Preemptive scheduling: When a process enters the state of running, the state of that process is not deleted from the scheduler until it finishes its service time.

In token Ring , hub is called Multistation Access Unit(MAU).