Date: Wed, 30 Mar 2005 17:50:54 -0600 (CST) From: Mark Jacobson To: 810-023-01@uni.edu Subject: Quiz on Monday... Assignment due on Monday too... Microcomputer Systems students, I forgot to remind the class that the assignment is also due on Monday, which is a good preparation for the FAT and sectors and clusters and magnetic disk (hard drives and diskettes) portion of the quiz. Topics for the quiz on Monday: 1. Be able to do and understand the CRC (Cyclic Redundancy Check) You have interactive practice quiz questions on the web page for this. 2. Understand the scanners handout and web page powerpoint presentation material, which is on the handout you have. 3. Know the concepts of how a hard drive works. Concepts of seek time to get the read/write head over the proper track, rotate time to get to the sector at about 7,200 rotations per minute or faster, sectors and clusters, FAT (file allocation tables), etc. Know the material in the textbook too that you read too. That should reinforce what we talked about in class and on the handouts. Know how to calculate the capacity of a diskette or disk platter. Example: You were told a diskette has 80 tracks per surface, and it records on both surfaces (the top side and the bottom side of the disk - i.e. double sided), and each surface or track is divided up into 18 pie shaped wedges, called sectors. And each sector contains 512 or 2 ^ 9 bytes, i.e. 1/2 kbyte is what one sector can hold. 2 times 2 ^ 9th is equal to 2 ^ 10th = 1 kb 2 * 80 * 18 2880 <-------- 2,880 sectors on a HD (High Density) DS (Double Sided) diskette 2880 * 2 ^ 9 1474560 <------- 1,474,560 bytes capacity of HD DS diskette 2880 / 2 2 to the 9th power is 1/2 kilobyte 1440 2 to the 10th is 1 kilobyte 1,440 kilobytes = 1.44 megabytes (approximately) HD DS diskettes usually are advertised as holding 1.44 MB, not as holding 1440 KB. 4. Understand the basics of security and the CIA acronym, or the CIAA, when you expand it to include Accessibility issue. 5. Understand the basics of cryptography and Caesar key cryptography. Know the terms plaintext and ciphertext and how to encrypt something from plaintext to ciphertext, given that the key = 3 or the key = 12, for example. 6. Be able to do the TIC tracing again, if asked on the quiz to understand or follow the execution of a Tiny Imaginary Computer as it fetches and executes instructions and loads and stores data into the ACC register, and fetches data items for the MULTIPLY or the ADD or the SUBTRACT or the DIVIDE or the other instructions. That should be enough material for this quiz. Mark