??sa ?p????e?s??

1
2

• ??sa ?p????e?s??

• ?e?a???a µ??µ??
• ?a???t???? d?s???
• S?st????e? d?s??? RAID
• ?pt???? d?s???
• ?a???t???? ta???e?
• ???a µ?sa ap????e?s??

2
?ef??a?? 2 ??sa ?p????e?s??
?e?a???a ???µ??

• ?ata????t?? (CPU registers)
• ???f? µ??µ? (cache memory, SRAM)
• ????a µ??µ? (main memory, DRAM)
• ???µ? flash (EEPROM-USB)
• ?a???t???? d?s??? (magnetic disk, floppy-hard)
• ?pt???? d?s??? (optical disk, CD-DVD)
• ?a???t??? ta???a (magnetic tape)

3
?ef??a?? 2 ??sa ?p????e?s??
?as??? ???t???a

• ???e???
• ?a??t?ta
• ??st??
• ????p?st?a
• ???te???sa
• ?e?te?e???sa
• ???te???sa

4
?ef??a?? 2 ??sa ?p????e?s??
?a???t???? ??s???

• ?? 1956 ? IBM ?atas?e?ase t?? p??t? d?s?? µe t??
  ???µas?a RAMAC (random access method for
  accounting and control) µe ????t???t?ta 5 MBytes.
  
• ? RAMAC ?ta? a??et? µe?a??te??? se µ??e??? se
  s??s? µe t??? s????????? d?s????, d??t? ?
  s??????? te???????a ep?t??pe? t?? a???s? t??
  a???µ?? t?? bits p?? µp????? ?a ??d???p???????
  a?? µ???da µa???-t???? ep?f??e?a?, µe ap?t??esµa
  ?a a????e? ? p????-t?ta ap????e?s?? (storage
  density) t?? d?s???.
• Ost?s?, a? ?a? ?? s?µe????? d?s??? e??a?
  ta??te???, µ????te??? ?a? ap????e???? pe??ss?te?a
  ded?µ??a, st??????ta? st?? ?d?e? te??????????
  a???? p?? ßas?st??e ?a? ? RAMAC.

5
?ef??a?? 2 ??sa ?p????e?s??
?a???t???? ??s???
6
?ef??a?? 2 ??sa ?p????e?s??
?a???t???? ??s???

• ? ep????????a µeta?? µa???t???? d?s??? ?a? CPU
  ep?t?????eta? µe t? ß???e?a t?? e?e??t?
  (controller).
• ? e?e??t?? e??a? ?pe?????? ??a t?? a?????s? ?a?
  t?? ap????e?s? t?? ded?µ????. ?p?s??, e??a?
  ?pe?????? ??a t? d?a?e???s? t?? ?atest?aµµ????
  t?µ??? (bad sectors).
• ? ep????????a µeta?? d?s??? ?a? CPU ???eta? se
  d?a???t? st?d?a ?? e???

7
?ef??a?? 2 ??sa ?p????e?s??
?a???t???? ??s???

• F?s? a?a??t?s?? (seek), Tseek µeta????s? t??
  ?efa??? ep??? ap? t?? ?at?????? t?????.
• F?s? pe??st??f???? ?a??st???s?? (rotational
  latency), Trot a?aµ??? µ???? ? ?at??????? t?µ?a?
  pe??se? ??t? ap? t?? ?efa??.
• F?s? ?etaf???? (transfer) ded?µ????, Ttrans ?
  ?efa?? d?aß??e? ? ???fe? ded?µ??a.
• ?s??e? Ttotal Tseek ?rot ?trans

8
?ef??a?? 2 ??sa ?p????e?s??
?a???t???? ??s???

• ? d?s??? s???de?eta? ?a? ap? µ?a e?d??µes?
  ap?-µ???t??? µ??µ? (buffer, cache) ??a t??
  p??s????? t?p???t?s? t?? ded?µ???? ??a µe????t???
  a?????s?.
• S?µa?t???? pa??µet??? ??a t?? a???p?st?a t??
  d?s??? e??a?
• µ?s?? ?????? µeta?? t?? ß?aß?? (MTBF), ?a?
• µ?s?? ?????? ??a ap??at?stas? (MTTR)

9
?ef??a?? 2 ??sa ?p????e?s??
?a?a?t???st??? s???????? µa???t???? d?s???
Seagate ST1181677LCV Western Digital WD25000JB Hitachi Ultrastar DK32EJ-14
????t???t?ta 182 Gb 250 Gb 147 Gb
?e??st??f? 7200 rpm 7200 rpm 10025 rpm
??s???/?efa??? 12/24 3/6 5/10
?????d??? 24247 16383 -
??a??t?s? (µ?s? t?µ?) 7.4 msec 8.9 msec 4.9 msec
?a??st???s? (µ?s? t?µ?) 4.17 msec 4.20 msec 2.99 msec
?etaf??? (µ???st? t?µ?) 47 Mb/sec 100 Mb/sec 100 Mb/sec
10
?ef??a?? 2 ??sa ?p????e?s??
S?st????e? ??s??? RAID

• RAID Redundant Array of Inexpensive/Independent
  Disks (1988)
• ???s? p????? µ???d?? d?s??? ??a f????te??/
  ta??te?? p??sp??as? ded?µ????.
• ????s? t?? a???p?st?a? ?a? t?? a????? se
  pe??pt?se?? ß??ß?? t?? µ?s??.

11
?ef??a?? 2 ??sa ?p????e?s??
RAID level 0

• ?a????? epa?????? ded?µ????

12
?ef??a?? 2 ??sa ?p????e?s??
RAID level 1

• ?a??ept?sµ?? (mirroring) ? s??as? (shadowing)
• ??p??s??? a???µ?? d?s???
• ??e??e?t?µata/µe???e?t?µata se R/W

13
?ef??a?? 2 ??sa ?p????e?s??
RAID level 2

• ???s? ??d???? d?????s?? ?a???
• ??s??? ded?µ???? ?a? d?s??? ?s?t?µ?a?
• ???????? d?aµ???asµ?? se ep?ped? se??d?? bit
  (data stripping) ??a ded?µ??a ?a? ?s?t?µ?e?

14
?ef??a?? 2 ??sa ?p????e?s??
RAID level 3

• ??aµ???asµ?? t?? se??da? se ep?ped? byte
• ??a? µ??? ep?p???? d?s??? ?s?t?µ?a?

15
?ef??a?? 2 ??sa ?p????e?s??
RAID level 4

• ??aµ???asµ?? t?? a??e??? se ep?ped? se??da?
• ??? ???eta? ? pa?a?????sµ?? se R/W ?

16
?ef??a?? 2 ??sa ?p????e?s??
RAID level 5

• ??aµ???asµ?? t?? a??e??? se ep?ped? se??da?
• ??aµ???asµ?? se??d?? ?s?t?µ?a?

17
?ef??a?? 2 ??sa ?p????e?s??
RAID level 6

• ??aµ?????e? ded?µ??a ?a? ?s?t?µ?a ?p?? t? RAID5.
• ?????e?e? ß??ße? se d?? d?s???? µe ???s? d??
  µe??d?? ?s?t?µ?a?.
• ?pa?te? d?p??s?? ???? ??a ta ded?µ??a ?s?t?µ?a?.

18
?ef??a?? 2 ??sa ?p????e?s??
S??d?asµ?? ?p?p?d?? RAID

• ????? ep?peda s??d?????ta?, ?p?te p????pt??? p??
  p???p???e? d?at??e??, µe d?af??et????? ßa?µ???
  a???p?st?a?.
• G?a pa??de??µa, s??d?????ta? t? RAID 0 µe t? RAID
  1 ????µe µ?a ??a s?st????a (RAID 01 ? RAID 10),
  ? ?p??a ??e? ta ?a?a?t???st??? ?a? t?? d??
  ep?p?d??.
• ?µ???? ? s??d?asµ?? t?? ep?p?d?? RAID 0 ?a? RAID
  3 d??e? t? s?st????a RAID 03 ???.

19
?ef??a?? 2 ??sa ?p????e?s??
?pt???? ??s???

• ? ?pt???? d?s??? (optical disk) ???s?µ?p??e?ta?
  ?????? ??a t?? ap????e?s? p????aµµ?t??, a??e???
  ?e?µ????, p???µes???? a??e??? (????, µ??s????,
  e??????, ta?????).
• ???s?µ?p?????ta? ep?s?? ?a? ?? ??a? e??????
  t??p?? pa?a????? a?t????f?? asfa?e?a?.
• ?e? s???st?ta? ??a ap????e?s? ded?µ???? on-line
  efa?µ????.

20
?ef??a?? 2 ??sa ?p????e?s??
?pt???? ??s???

• ??a??????µe d?? t?p???
• WORM write-once read-many
• Rewritable write-many read-many
• ???? d?????s? d?s???
• CAV constant angular velocity
• CLV constant linear velocity

21
?ef??a?? 2 ??sa ?p????e?s??
?pt???? ??s??? CLV

• ? ????a?? ta??t?ta a????eta? ?a??? ?? ?efa???
  ??????ta? p??? t?? ????a pe??st??f??, ?ste ??e?
  ?? e???af?? ?a pe????? ??t? ap? t? µ??a??sµ?
  a?????s?? µe t?? ?d?? ???µ?.
• ???a? d??at?? ?a ??e?as???? pe??ss?te?e? t?? µ?a?
  p??sp??e?e? µ???? ?a e?t?p?s?e? ? a?a??t??µe??
  ?t?a?t??, ?p?te ? a?a??t?s? e??a? ß?ad?te?? ap?t?
  se s?s?e??? CAV (100ms µe ta??t?te? 52?).
• ??e????t?µa ?a??te?? ???s? t?? ????? ????
  ?µ???µ??f?? p????t?ta? ap????e?s??.
• ?e?????t?µa ? ?efa?? de? µp??e? ?a µet??se? t??
  at???t??? p?? p??spe??? ???? µe????? ta??t?ta?.

22
?ef??a?? 2 ??sa ?p????e?s??
?pt???? ??s???

• ? ?pt???? d?s??? ??e? d??µet?? 12cm p?? e??a?
  e??te???? (ap? ??t?) ?atas?e?asµ???? ap?
  p???a???a???? p?ast??? ?????.
• ?? p???a???a???? ????? a??????e? es?te???? ??a
  st??µa f?t?e?a?s??t?? ???st???? ??s?a? ?a?
  es?te?a ?p???e? ep?st??s? ap? f???? a???µ?????.
• ?? s??????? p???? t?? ?pt???? d?s??? e??a?
  pe??p?? 1.2mm.

23
?ef??a?? 2 ??sa ?p????e?s??
?pt???? ??s???

• ?????aµµa ?pt???? d?s???.

24
?ef??a?? 2 ??sa ?p????e?s??
?pt???? ??s???

• Se ??a? ?e?? ?pt??? d?s?? ? ep?f??e?a t??
  ???st???? ??s?a? e??a? ?µ?d?afa???.
• ? ap????e?s? t?? ded?µ???? p?a?µat?p??e?ta? µe t?
  ß???e?a d?sµ?? laser p?? µetat??pe? t? ???st???
  ??s?a se ad?afa??.
• ? a?????s? t?? ded?µ???? p?a?µat?p??e?ta? µe t?
  ß???e?a d?sµ?? laser ?aµ???te??? ?s????. ?ta? ?
  d?sµ? pe??se? ap? s?µe?? t?? ???st???? ??s?a? p??
  e??a? ?µ?d?afa???, ? d?sµ? ?a a?a??as?e? µ?s? t??
  ep?st??s?? a???µ?????. ?????? de? ?a ?p???e?
  a????as?. ?ts? µp????µe ?a d?a????s??µe ta bits
  t?? p????f???a? p?? pe????eta? st?? ?pt??? d?s??.

25
?ef??a?? 2 ??sa ?p????e?s??
?pt???? ??s???

• ?a ded?µ??a ap????e???ta? se spe???e?d? t?????
  ap? t? ???t?? t?? d?s??? p??? ta ???.
• ? µ??f?p???s? ?e??e?ta? µe ß?s? µ?a a?t??a t??
  d?s???, ?p?te µ?a ??e?? ?t?a?t?? ß??s?eta? µeta??
  d?? d?ad?????? t?µ?? a?t??a? ?a? spe???e?d???
  at???t??.

26
?ef??a?? 2 ??sa ?p????e?s??
?pt???? ??s???

• ?? s????? t?? d?ad?????? ??e??? at???t?? ?d?a?
  ????t???t?ta? ?e??e?ta? ?t? ap?te?e? µ?a ????
  (zone), ?p?te ? d?aµ??f?s? ???µ??eta? p?????????
  (multizone).
• ?p???e? µ?a ?e?t???? at???t?? p?? e?t?p????ta?
  ????? t? ?????ß??a pa???d??µ??? µeta????s? t??
  ß?a????a a??? µe µ?a pe??st??f??? ????s? e???
  fa??? st? µ?-?a??sµ? t?? ?efa???. ??t? ? ?e?t????
  t?? at???t?? ???µ??eta? e???? pa?????? (proximal
  window).
• ? pe??st??f? µp??e? ?a ???e? µ???? µ?a µ???st?
  ????a, ?p?te t? µ??e??? t?? e???? pa?a????? e??a?
  s?et??? pe?????sµ???.

27
?ef??a?? 2 ??sa ?p????e?s??
?pt???? ??s???

• ?as??? ?a?a?t???st??? t?? ap?d?s?? e??a? ? ??????
  p??sp??as?? ?a? ? ta??t?ta µetaf????. S??????
  µet??ta? µe ??a? a???µ?, p? 52?, p?? d????e? ?t?
  ??a? s???e???µ???? d?s??? e??a? 52 f????
  ???????te??? ap? ??a d?s?? a?af????.
• S?st????a ?pt???? d?s??? (jukebox) e??a? µ?a
  s?s?e?? µe p?????? ?pt????? d?s???? p??
  e?a???s-s??ta? µe ??µp?t????? µ??a??sµ??? a?????a
  µe t? ??t?s? se µe???e? ??f?a??? ß?ß??????e?.
• S?µa?t???? e??a? ? ?????? e?a??a??? d?s??? st?
  p?at?.

28
?ef??a?? 2 ??sa ?p????e?s??
?a???t??? ?a???a

• St? de?aet?a t?? 1950 ? µa???t??? ta???a
  (magnetic tape) ?ta? t? ßas??? µ?s? ap????e?s??
  t?? ?p???-??st?? mainframes.
• ?? ?a? ap? t?? a???? t?? de?aet?a? t?? 1960 ?
  µa???t???? d?s??? ?a??e?????e ?? t? ßas??? µ?s?
  ap????e?s?? se µ???? ?a? µe???a ?p?????st???
  s?st?µata, ? µa???t??? ta???a s??e???e? s?µe?a ?a
  ap?te?e? ??a ?aµ???? ??st??? ß????t??? µ?s?
  ap????e?s??.

29
?ef??a?? 2 ??sa ?p????e?s??
?a???t??? ?a???a

• ?atas?e???eta? ap? ?ept? st??µa p?ast???? ??????,
  t? ?p??? ?a??pteta? µe µ???? ??µµ?t?a ap? ??e?d??
  t?? s?d???? ? µe ??p??? ???? µa???t??? ?????.
• G?a t?? ap????e?s? ded?µ???? ???s?µ?p??e?ta? µ?a
  ?efa?? p?? d??eta? ??e?t???? ?e?µa µe ap?t??esµa
  ?a µa???t??eta? t? s???e???µ??? tµ?µa t??
  µa???t???? ??????.
• ?at? t?? a?????s? t?? ded?µ???? ? ?efa??
  a?a-??????e? t?? µetaß???? st?? p???s? t??
  µa???t???? ?????? ?a? e??s??e? t? s?µa st??
  ???d?.

30
?ef??a?? 2 ??sa ?p????e?s??
?a???t??? ?a???a

• ?a ded?µ??a ap????e???ta? se 9 pa??????e?
  at???t???. ???e ?t?a?t?? pa??st? se??? bits p??
  ?ata???????ta? µe p????t?ta ap????e?s?? s??????
  6250 bits/??tsa (bpi). ?at? t??
  a?????s?/ap????e?s? ded?µ???? ? ta???a ???e?ta?
  µe t? ?e??µe?? ta??t?ta a?????s??/ap????e?s??
  (read/write speed).
• ?at? t?? t??a?a a?a??t?s? p??pe? µ?a s???e???µ???
  e???af? ?a f??se? eµp??? ap? t?? ?efa?? ?????
  apa?a?t?ta ?a ???e? epe?e??as?a t?? p??????µe???
  e???af??. ??te ? ta???a ???e?ta? µe p??? µe????
  ta??t?ta.

31
?ef??a?? 2 ??sa ?p????e?s??
?a???t??? ?a???a

• Se?ß?µ??a??sµ?? e????e? ?ste ?a µ?? ?atast?afe?
  ? ta???a ?at? t?? st?se?? ?a? t?? e?????se??,
  ??at? ? ep?t????s? ? ep?ß??d??s? e??a? 25g.
• St?? ta???a ?p?????? d?ast?µata ????? ded?µ??a,
  ?ste ?a µe???e? ? ta??t?ta µ???? t? ep???µ?t?
  s?µe?? ?a? ?a ???e? ?at?p?? a?????s? ?
  ap????e?s?. ??t? ta d?ast?µata ???µ????ta? ?e??
  µeta?? t?? e???af?? (interrecord gaps).
• ? ?????? p?? apa?te?ta? ??a t? s???s? t?? ?e???
  ???µ??eta? ?????? e?????s??/st?s?? (start/stop
  time). ?? µ??e??? t?? ?e??? e??a? µe?a??te?? ?s?
  µ?-???te?? e??a? ? p????t?ta ap????e?s?? (0.6
  ??tse?).

32
?ef??a?? 2 ??sa ?p????e?s??
?a???t??? ?a???a

• ? ?????a t?? e???af??, ?p?? e??a? ???st? ap? t??
  p????aµµat?sµ?, st?? µa???t???? ta???e?
  ???µ??eta? ?????? e???af? (logical record) ?a?
  ?a?a?t????eta? ap? t? a?t?st???? µ????.
• ?? ??????? e???af?? ?µad?p?????ta? se µ????
  s????a ?a? ap?te???? µ?a f?s??? e???af? (physical
  record) µe t? a?t?st???? µ????. ?p?µ????, ??a
  ?e?? µes?-?aße? µeta?? d?? f?s???? e???af??.
• ?a?????ta? ???s?µ?p???s?? ????? (storage
  utili-zation factor) e??a? ? ????? t?? µ????? t??
  f?s???? e???af?? p??? t? ?????sµa t?? µ????? t??
  f?s???? e???af?? ?a? t?? ?e???.

33
?ef??a?? 2 ??sa ?p????e?s??
?a???t??? ?a???a

• ?? p????? t?? ??????? e???af?? p?? pe????eta? se
  µ?a f?s??? e???af? ???eta? pa?????ta?
  ?µad?p???s?? (blocking factor). ? f?s??? e???af?
  p??pe? ?a e??a? ?s? t? d??at? µe?a??te??, ?ste ?a
  e?a??st?p????e? t? s??????? µ??e??? t?? ?e???
  t?? ta???a?, a??? ta?t?????a p??pe? ?a ???? st??
  ap?µ???t???? µ??µe?.
• St?? 8 at???t??? p?? ß??s???ta? se µ?a ?ata????f?
  ??aµµ? ap????e?eta? ??a byte. ????? Hamming
  ???eta? t? p????? t?? ?ss?? se ??a byte. ? ??at?
  ?t?a?t?? ???s?µe?e? ??a t?? ap????e?s? t?? bit
  ?s?t?µ?a? (parity bit).

34
?ef??a?? 2 ??sa ?p????e?s??
?a???t??? ?a???a

• St?? ??t?a ?s?t?µ?a (even parity) t? bit
  ?s?t?µ?a? e??a? 0/1 ?ste t? ß???? Hamming ?a
  e??a? ??t??. St?? pe??tt? ?s?t?µ?a (odd parity)
  t? bit e??a? 0/1 ?ste t? ß???? ?a e??a? pe??tt?.
  ?? bit ?s?t?µ?a? ???s?µ?p??e?ta? ??a t??
  ?ata????f? (vertical) ??e??? ?a??? t?? bits.
• ?? d?ap?st??e? ????? ?at? t?? a?????s? t??
  ta???a?, t?te e?e???p??e?ta? µ?a d?ad??as?a
  d?a??p??. ?p??e????-?ta? p????? p??sp??e?e?
  a?????s?? t?? s???e???µ???? s?µe??? t?? ta???a?
  µ????? ? t? ????? ?a e?t?p?s?e? ? ? a???µ?? t??
  epa?a???e?? ?a f??se? µ?a µ???st? t?µ?.
• ?p?s?? pe???d??? t?p??et???ta? bytes ?s?t?µ?a?
  ??a t? d?e??????s? ?at? µ???? (longitudinal)
  e?????? d?ad?????? bytes.

35
?ef??a?? 2 ??sa ?p????e?s??
?e???????e? ?a???t???? ?a???a?

• G?aµµ????/ep?µ???? t?p?? (linear/longitudinal)
• ?a??? te???????a (9 ?t?a?t?? µe ?s?t?µ?a
  ??t?a/pe??tt?)
• ?f??e?d??? ap????e?s?? (serpentine recording)
• ?p????e?s? st?? at???t??? ?a? ?at? t?? 2 f????
  e?a????
• ?????e?d??? s???s?? (helical scan)
• ?p????e?s? ?p? ????a 10-20? ???s? se VCR
• ?????s?a? ap????e?s?? (transverse recording)
• ?p????e?s? se ?ata????fe? at???t??? ???s? se
  sensors

36
?ef??a?? 2 ??sa ?p????e?s??
?e???????e? ?a???t???? ?a???a?

• (a) ?f??e?d??? ap????e?s??
• (ß) ?????e?d??? s???s??
• (?) ?????s?a? ap????e?s??

37
?ef??a?? 2 ??sa ?p????e?s??
?a???t??? ?a???a

• Jukebox µe µa???t???? ta???e? e??a? s?s?e??? µe
  te??st?e? ????t???t?te? (t?? t???? TB) ??a
  e?d???? efa?µ???? (p? ??a d???f????? ded?µ??a
  t??ep?s??-p?s?? ??p).
• ????? p?????? ?d????? (p?at?) ??a t?? e??p???t?s?
  t?? ta?????.
• ??a??????ta? ap? ????? a???p?st?a (p?. MTBF
  250.000 ??e? 29 ?t?, 2.000.000 e?a??a???).

38
?ef??a?? 2 ??sa ?p????e?s??
???a ??sa ?p????e?s??

• ????st???a d??t??te? ???te?, ?a?t?ta???e?,
  µa???t??? t?µpa??.
• S?s?e??? µa????? ap????e?s?? (mass storage)
  ???s?µ?p????? p????? ap? ?as?te? ??a µa????????a
  ap????e?s? se s??d?asµ? µe µa???t????? d?s????
  ??a t?? ap????e?s? t?? ded?µ???? ?at? t??
  epe?e??as?a.
• ???µe? µa???t???? f?sa??d?? (magnetic bubble
  memories) ????? ?a???? ??????? p??sp??as?? (ap?
  4 µ???? 7 ms), a??? ?ste???? se ????t???t?ta (ap?
  92.000 µ???? 1310.720 bits) ?a? ????? µetaf????
  (ap? 50.000 µ???? 5000.000 bps).

39
?ef??a?? 2 ??sa ?p????e?s??
???a ??sa ?p????e?s??

• S?s?e??? ?µ?a????µ?? d?s??? (semiconductor disks)
  eµfa??s???a? eµp????? t? 1978 ?a? ??t?te ?????
  ???-??se? s?µa?t??? e?????? ?a? efa?µ??? se
  pe??pt?se?? ap????e?s?? ß?ß???????? p????aµµ?t??,
  ?ata????? ? p??s?????? a??e??? e??as?a?.
• ??a??????ta? ap? p??a p??? ??????? p??sp??as?
  (?p?? 0,5 ms), s?et??? µe???? ????t???t?ta (?p??
  700 ?b), ?aµ??? ??st?? ?a? ?ata????s? ?e?µat??.

40
?ef??a?? 2 ??sa ?p????e?s??
???a ??sa ?p????e?s??

• ? ?pt??? ta???a (optical tape) ??e? d??at?t?ta
  ap???-?e?s?? te??st??? ????t???t?t?? se p???
  µ???? ???? (ap????e?s? sta 80 t?? ep?fa?e?a? se
  a?t??es? µe 50 ??a ?pt??? d?s??, p????t?ta
  ap????e?s?? gt25 f???? se s??s? µe ?pt??? d?s??).
• ? ?????af?a (holography) a?af??eta? st??
  t??sd??-stat? ap????e?s? ded?µ???? µ?sa se ??a
  ???sta???.
• St? fa???µe?? pa??de?s?? ??e?t?????? (electron
  trapping), st??µa f?sf???? d??eta? f?? ?a?
  e?p?µpe? ??e?t????a p?? ap????f??ta? ap? a????µ?
  ????. ?e f?? d?af??et???? s????t?ta? ta
  ??e?t????a e??????ta? ?a? e?p?µp??? f?t???a.

41
?ef??a?? 2 ??sa ?p????e?s??
???a ??sa ?p????e?s??
?pt???? d?s??? ?pt??? ta???a ?????af?a ?a??de?s? ??e?t??????
??e??e?t?µata ???µ??a???? p??t?p? ??st??/Mb ?????e?a ???? ?????t?ta ap????e?s??, ?a?a?????sµ?? ?p????e?t??? ??a??t?ta, ?a??t?ta µetaf????
????t???t?ta 5 Gb se d?s?? 15 cm 200 Gb se ta???a 3480 ft 1 Gb se ???ta 30x30 mm 10 Gb se d?s?? 13 cm
????a ???s? ?p??ßas? e??aµpt?? d?s??? ???e????t?s? F???t? s?st?µata ???te?
??ta????st?? F???t?? µa???t???? d?s??? ?a???t??? ta???a se ???ta ?a???t???? d?s??? ???a?e? d?s??? RAID
?e???e?t?µata ?????? a?a??t?s?? Se???a?? p??sp??as? ?atast??f??? a?????s? ?atast??f??? a?????s?
42
?ef??a?? 2 ??sa ?p????e?s??
??as??des? s?s?e??? ap????e?s??
Direct attached storage - DAS H µ???da
ap????e?s?? s??d?eta? ?µesa st?? e??p???t? (p?
µ?s? SCSI). ? e??p???t?? e??a? ?pe???-??? ??a t?
d?a?e???s? t?? µ???da? ap????e?s?? ?a? e????e?
t?? p??-sßas? se ???a s?st?µata µ?s? ??p????
s?st?µat?? d?aµ???asµ?? (p? NFS). ?? µe?????t?µa
t?? te???-??? e??a? ?t? se pe??pt?s? ß??ß?? t??
e??p???t? de? ?p???e? d??at?-t?ta p??sp??as?? t??
ded?µ???? ap? ???a s?st?µata.
43
?ef??a?? 2 ??sa ?p????e?s??
??as??des? s?s?e??? ap????e?s??
Network attached storage - NAS ??a a?t???µ?
s?s?e??? d?a?e???-?eta? t?? µ???de? ap????e?s??,
µe e?d??? ?e?t??????? s?st?µa ??a d??at?t?te?
d?aµ???asµ?? a??e???. ? d?a?e???st?? t??
s?st?µat?? µp??e? ?a a????e? t? d?aµ??f?s?
???s?µ?p????ta? e?d??? e??a?e?a ????sµ????. ?
ta??t?ta µetaf???? ded?µ???? pe??????eta? ap? t?
d??t?? p?? ???s?µ?p??e?ta? ??a t? d?as??des? t??
µ???d?? ap???-?e?s??.
44
?ef??a?? 2 ??sa ?p????e?s??
??as??des? s?s?e??? ap????e?s??
Storage area network - SAN ???s?µ?p??e?
?e?t????p???µ??? µe??d?????a ??a t? d?as??des?
t?? e??p??et?? µe t?? µ???de? ap????e?s?? s??????
µ?s? ?pt?-??? ????. G?a t? d??µ?????s? t??
pa??t?? ded?µ???? ap?/p??? t??? e??p???te?
p???/ap? t?? µ???de? ap????e?s??,
???s?µ?p?????ta? µeta???e?? (switches).
??a????eta? ??a t?? ????? t?? ep?d?s? ?a? t?
d?a?es?µ?t?ta.