============================== Assignment #09 - Disk Geometry ============================== - Ian! D. Allen - idallen@idallen.ca - www.idallen.com Available online: Wednesday November 11, 2009 Due date in the Blackboard Assignment Area: due at 08:00 AM on Wednesday November 18, 2009 Do *not* use the DigitalDropbox to submit your answers. Answers will be posted after the due date/time so that you can check your answers before coming to class and ask questions in class. Please check your answers (and my answers!). I go over each assignment in class if there are questions about the answers. No questions means no review. Submission method: Via the "Assignments" DAT2343_Assignment_09 upload. Due to bugs in Blackboard, you can only submit your Assignment to me *once*. After that, you cannot submit any more times. If you need to re-submit it, you have to ask me to clear your previous submission. Do *not* use the DigitalDropbox to submit your answers. Answers will be posted shortly after the due date/time. Upload Assignment file name: assignment09.txt The name must be exactly as given. Typing mistakes in the name mean no credit. Be precise. (Your userid is not required.) Upload only plain text, not HTML, not MSWord. No fonts. Plain text only. Plain text only. Did I mention that the format is plain text? ------------------ If not specifically told otherwise, assume that a "sector" is 512 bytes. 1. How many MBytes does a disk hold if C/H/S = 512/6/20? ANSWER: 2. True/False: A program writing 10,000 bytes to a disk will create a 10,000-byte sector on the disk to hold the data. ANSWER: REASON: 3. Why do many file systems use "allocation units" instead of single sectors? ANSWER: 4. On a Windows system with a cluster size of 32, how much space (on average) is wasted at the end of every file on the disk? Answer in KBytes. ANSWER: 5. True/False: With "Contiguous Space Allocation" it is possible to have 20 sectors of free space but still be unable to allocate a 10-sector file. ANSWER: REASON: 6. Using "Extent-Based File Allocation" on a disk with a block of 9 contiguous unused sectors and another block of 8 contiguous unused sectors and no other unused space, what is the largest file possible using these primary/secondary space requests (see 19PhysicalFiles.htm): a) 10 primary, 2 secondary: ANSWER: b) 8 primary, 4 secondary: ANSWER: c) 5 primary, 5 secondary: ANSWER: d) 4 primary, 4 secondary: ANSWER: e) 4 primary, 3 secondary: ANSWER: f) 2 primary, 1 secondary: ANSWER: 7. How many bytes are used by the Boot Sector (Boot Block) on most disk drives? ANSWER: 8. Where is the Boot Sector located on a disk drive? ANSWER: 9. Given the structure of an MS-DOS Boot Sector (19PhysicalFiles.htm): a) What is the maximum size of a sector, in bytes and KBytes? ANSWER: b) What is the maximum number of sectors per cluster? ANSWER: c) What is the maximum number of FAT copies? ANSWER: d) What is the maximum number of ROOT directory entries? ANSWER: e) What is the maximum number of sectors per FAT? ANSWER: f) What is the maximum number of sectors per track? ANSWER: g) What is the maximum number of heads? ANSWER: h) What is the hex attribute byte value for "Read-Only, Hidden, System"? ANSWER: i) What is the hex attribute byte value for "Subdirectory, Archive Needed"? ANSWER: 10. What is the difference between a track sector number and an absolute sector number? ANSWER: 11. If a particular disk has 2 surfaces and 18 sectors/track, what is the C/H/S (Cylinder/Head/Sector) location of absolute disk sector 454 (all values in decimal)? ANSWER: 12. From the DUMP given in 20MSDOSDiskStructure.htm, look at the first 32 bytes of the Sample Boot Sector. If memory offset 0x0010 contained 03 instead of 02, what would be the layout of the disk? Fill in the twelve new values in the "What is the layout of this Disk" table: Data Structure Number of Sectors (hex) Start/End Sectors (hex) a) b) c) d) e) f) g) h) i) j) k) l) 13. From the DUMP given in 20MSDOSDiskStructure.htm answer these questions about the directory entry for "IO.SYS": a) What are the Attributes of IO.SYS (in English)? ANSWER: b) What is the starting cluster number (in hex and decimal)? ANSWER: c) What is the starting absolute sector number (in hex and decimal)? ANSWER: d) What is the size (in hex and decimal)? ANSWER: 14. What DEBUG commands loads 10 (decimal) sectors from the floppy disk, starting at absolute sector 25 (decimal) into memory at offset zero? ANSWER: 15. What does an MS-DOS Attribute byte value of 0x0F mean? ANSWER: 16. How does MS-DOS/Windows indicate that a file or directory has been deleted? ANSWER: Submission method: Via the "Assignments" DAT2343_Assignment_09 upload. Upload Assignment file name: assignment09.txt The name must be exactly as given. Typing mistakes in the name mean no credit. Be precise. (Your userid is not required.)