8.9. The IBM System/370 architecture uses a two-levelmemory structure and refers to the two levels as segmentsand pages, although the segmentation approach lacks manyof the features described earlier in this chapter. For the basic370 architecture, the page size may be either 2 kB or 4 kB,and the segment size is fixed at either 64 kB or 1 MB. For the370/XA and 370/ESA architectures, the page size is 4 kB andthe segment size is 1 MB. Which advantages of segmentationdoes this scheme lack? What is the benefit of segmentationfor the 370? 8.7. In the VAX, user page tables are located at virtualaddresses in the system space. What is the advantage ofhaving user page tables in virtual rather than main memory?What is the disadvantage?

Initial consideration: Considering the architecture for the IBM System/370 that is capable of…

Answered: 8.7. In the VAX, user page tables are…

8.7. In the VAX, user page tables are located at virtual addresses in the system space. What is the advantage of having user page tables in virtual rather than main memory? What is the disadvantage?

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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Suppose that you have a very simple file system (VSFS) using i-node to manage disk data blocks, where the disk block size is 4096 bytes. Disk addresses and file block pointers take 32 bits (4 bytes), and the i-node contains 10 direct pointers, one single-indirect pointer and one double-indirect pointer. Assume an index block is the same size as a data block (both 4096 Bytes). If there is a file having 45,000 bytes of data and it has never been accessed, we only assume the file's i-node is in memory, but none of the rest of the file. If the user process wants to read the entire file into the memory, how many disk blocks (including both data blocks and index block(s)) would be brought into the main memory? O a. 11 O b. 10 O C. 12 O d. 1035 e. 1034
(a) FCFS with a single Ready Queue. A process gets scheduled once one of the CPUsis available. When both CPUs are available, we select CPU1. (b) FCFS with a Ready Queue per CPU. Processes A, B, and C go to CPU1 and processesD, E, and F go to CPU2. (c) HRRN with a single Ready Queue. A process gets scheduled once one of the CPUsis available. When both CPUs are available, we select CPU1.
Compare the main memory organization schemes of contiguous-memory allocation, pure segmentation, and pure paging with respect to the following issues: a. External fragmentation b. Internal fragmentation c. ability to share code across processes
8.9. The IBM System/370 architecture uses a two-level memory structure and refers to the two levels as segments and pages, although the segmentation approach lacks many of the features described earlier in this chapter. For the basic 370 architecture, the page size may be either 2 Kbytes or 4 Kbytes, and the segment size is fixed at either 64 Kbytes or 1 Mbyte. For the 370/XA and 370/ESA architectures, the page size is 4 Kbytes and the segment size is 1 Mbyte. Which advantages of segmentation does this scheme lack? What is the benefit of segmentation for the 370?
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Assume a hypothetical system where disk space has been divided into disk blocks of 25 bytes. The operating system needs to allocate space for a 120-byte file called output_log. Create a diagram for each of the three allocation methods showing how the space might be allocated and what information would be stored in the file directory for that file. For Linked Allocation, assume the first 5 bytes of each block is used for the pointer
Q.No.2. Answer the following short questions to the point. In what Nachos file was StartProcess implemented? What kind of pages in a process’ virtual address space are usually protected as “Read Only”? Is it possible to implement a file system inside of a file stored in another file system?
7.2. Consider a fixed partitioning scheme with equal-size partitions of 2¹6 bytes and a total main memory size of 224 bytes. A process table is maintained that includes a pointer to a partition for each resident process. How many bits are required for the pointer?
Description:The project I am working on needs to demonstrate how two processes (parent and child) can communicatethrough a shared memory region, with the child process writing a value to the shared memoryand the parent process reading that value. This is my code and I wont run. Can you help: #include <stdio.h>#include <stdlib.h>#include <sys/types.h>#include <sys/ipc.h>#include <sys/shm.h>#include <unistd.h> #define SHM_SIZE 1024 /* shared memory size */ void error_exit(const char *msg) { perror(msg); exit(EXIT_FAILURE);} int main() { key_t key; int shmid; char *data; // Create a unique key for shared memory if ((key = ftok("shared_memory.c", 'R')) == -1) { error_exit("ftok"); } // Create the shared memory segment if ((shmid = shmget(key, SHM_SIZE, 0644 | IPC_CREAT)) == -1) { error_exit("shmget"); } // Attach the shared memory segment to our data space data = shmat(shmid, (void *)0, 0); if…
What is the best way to handle virtual memory using explicit memory mapping and function calls?
Turn on the Non-executable Stack Protection Operating systems used to allow executable stacks, but this has now changed: In Ubuntu OS, the binary images of programs (and shared libraries) must declare whether they require executable stacks or not, i.e., they need to mark a field in the program header. Kernel or dynamic linker uses this marking to decide whether to make the stack of this running program executable or non-executable. This marking is done automatically by the gcc, which by default makes stack non-executable. We can specifically make it nonexecutable using the "-z noexecstack" flag in the compilation. In our previous tasks, we used "-z execstack" to make stacks executable. In this task, we will make the stack non-executable. We will do this experiment in the shellcode folder. The callshellcode program puts a copy of shellcode on the stack, and then executes the code from the stack. Please recompile call shellcode.c into a32.out and a64.out, without the "-z execstack"…