[理工] Disk size 計算

[ex8338 (三十八)]

  A 255-GB disk has 65536 cylinders with 255 sectors per track
and 512 bytes per sector. How many platters and heads does this
disk have?

請問一下這題要怎麼算

本魯一直搞不太懂Disk的計算題

  Consider a computer system that has cache memory,main memory and disk,
and an operationg system that uses virtual memory. It takes 2ns to
access a word from the cache, 10ns to access aword from the main memory
, and 10ms to access a word from the disk. If the cache hit rate is 95%
and main memory hit rate (after a cache miss) is 99%,what isthe
average time in ns to access a word?

謝謝！



--
※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 150.116.123.65
※ 文章網址: https://www.ptt.cc/bbs/Grad-ProbAsk/M.1487226082.A.B63.html
※ 編輯: ex8338 (150.116.123.65), 02/16/2017 14:39:52
推 yorunohoshi: platters and heads應該是算有幾個磁盤 設有X個
→ yorunohoshi: X*65536*255*512 B = 255 GB  解X=32
→ yorunohoshi: 第二題用AMAT算
→ TWkobe: 補充一樓 如果是雙面可寫platter只要16個 head仍然32個
→ hibiscus520: 恩恩同樓上,現在偶 雙面的disk了
→ hibiscus520: 第二題AMAT: 2ns*+0.05*10ns+0.01*10ms
→ yorunohoshi: 感謝補充orz