Homework on Secondary Storage
Due: July 18, 2000
Given a count-data organization where the extra space used by the count
subblock and interblock gaps is 185 bytes and
| average seek time |
9.5 msec |
| rotational delay |
5.7 msec |
| transfer rate |
11.7 msec/track |
| bytes per sector |
512 |
| sectors per track |
40 |
| tracks per cylinder |
11 |
| tracks per surface |
1,331 |
| interleave factor |
1 |
| cluster size |
8 sectors |
| smallest extent size |
5 clusters |
You have a file with 300,000, 100-byte records you need to store. If not
otherwise stated assume a blocking factor of 10.
- How many blocks can be stored on one track?
- How many records?
- How much wasted space (non-data bytes) per track in example 1?
- Make a graph (use a spreadsheet) that shows the effect of block size on storage
utilization. Assume all appropriate blocking factors.
- Ignoring blocking factors less than 10 and the whole track, what are the best and worst
blocking factors?
- How many cylinders are required to hold the file (blocking factor 10)?
- How long will it tack to access one track?
- How long will it take to access the file sequentially using various blocking factors as
in question 4?
- Make chart displaying access times vs blocking factor.
- How long will it take to retrieve one specific record, worse case?