Skip to content

Latest commit

 

History

History
56 lines (38 loc) · 1.84 KB

README.md

File metadata and controls

56 lines (38 loc) · 1.84 KB
Raw

Day 1

Today, you'll create two base level API methods for the FileSystem and also reserve space for the disk.

Task 0

Go through the filesystem.h file.

Task 1

Update the constructor day1/FileSystem.cpp

  • EDIT 1 (line 10): alreadyExists, diskSize_k
  • EDIT 2 (line 28): numberOfSectors_k
  • EDIT 3 (line 34): reservedSectors_k

Hints for edit 2, 3:

Consider a disk of size 1MiB (2^20 bytes) with sector size 512 bytes (2^9). It has total 2^11 sectors. Each sector can store status of 512/4 = 128 (= 2^7) sectors. so for 2^11 sectors, we need to reserve 16 (= 2^4) sectors.

The factor of 4: 4 bytes == sizeof(int). Edit your code if different on your workstation. We need one integer to store the status of a sector. You might need a long int if you have a lot of sectors.

Task 2

Go through day1/createDisk.cpp. The minimum unit of read or write in a disk is a sector. We'll use this fact throughout the assignment and to make things easier to handle, we make two base level API methods - readSector and writeSector.

Task 3

Update day1/readSector.cpp and day1/writeSector.cpp for byteOffset variable. This will tell you which bytes (total sectorSize_k bytes at a time) need to be read/written from/to the disk.

  • EDIT: byteOffset
  • EDIT: handle errors

Task 4

Test the work done and debug if needed.

$ make
$ ./filesystem
Enter path to disk: mydisk.bin
Enter disk size in MiB : 1
(myFileSystem)> read 0
(myFileSystem)> read 1
(myFileSystem)> write 0
Enter alphabet: a
(myFileSystem)> read 0
(myFileSystem)> read 1

You should test your code for various sectors, as this a very import base method, which will be used throughout the assignment.

Also, handle some errors like if sector_no is negative or doesn't exist in disk, in day1/readSector.cpp and day1/writeSector.cpp.