Technical Questions

Hubs regenerate electrical signals, which are specified at the Physical layer.

Windows NT uses protection mechanism called rings provides by the process to implement separation between the user mode and kernel mode.

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.

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.

MAU is Multistation Access Unit

No Windows NT is not so, because its not implemented in object oriented language and the data structures reside within one executive component and are not represented as objects and it does not support object oriented capabilities.

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.

Use the concept of register-retiming.

divide the totla combinatorial delay in two segments such that individually the delay is less the clock period.

this can be done by inserting a flip-flop in the combinational path.

e.g.,

clock period --- 5 ns

total cominational delay ---- 7

then divide the 7ns path in two path of 4 or 3 (best resutls are obtained if delays are  same for both path i.e 3.5ns) by inserting a flip-flop in between.