GATE 2020 Computer Science and IT Question Paper with answer

Consider A → PQ, A → XY are the productions of a grammar P, Q, X, A are non-terminals, s is synthesized attribute, i is an inherited attribute.

  Rule 1: P.i=A. i+2, Q.i=P .i+A .i,A .s=P .s+Q .s

  Rule 2:  X.i=A. i+Y .s and Y .i=X .s+A .i

  Which of the following is TRUE?

Which of the following statements is TRUE?
1. Symbol table is accessed only during lexical analysis and syntax analysis.
2. Compilers for programming L that support recursion necessarily need heap storage for memory allocation in the runtime environment.
3. Errors violating the condition any variable must be declared before its use are detected during syntax analysis.

A non – pipeline processor having 2.5 GHz clock frequency. Where each instruction takes 5 cycles and when this processor utilize with the same 5 stage pipeline having 2 GHz clock frequency and 30
% are memory instructions 60 % are ALU instruction and the remaining are branch instruction. Given that 5% memory instruction takes 50 stall cycles and 50% branch instruction takes 2 cycles then what will be the speed up when pipeline processor is used over non- pipeline processor___

In a decoder with in input lines and n output lines, then 1 KB RAM is given and now find (m + b)

Given main memory with single level paging main memory access time 100 ns TLB access time 20 ns. TLB hit ratio 95% page fault rate 10% and when there is page fault in 20% cases it uses write back and retrieve page from secondary memory with 5000 ns access time calculate average access time? With upto 1 decimal place. [Bonus]