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CMSC424: Database Design

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Flash memory - limited number of write/erase cycles; non ... Western Digital. 500GB. Weight (max. g): 600g. CMSC424, Spring 2006. 10. CMSC424, Spring 2006 ... – PowerPoint PPT presentation

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Title: CMSC424: Database Design


1
CMSC424 Database Design
  • Data Storage

2
Storage Hierarchy
3
Storage Hierarchy
  • Cache - Super fast volatile
  • Main memory - 10s or 100s of ns volatile
  • Flash memory - limited number of write/erase
    cycles non-volatile, slower than main memory
  • Intel announcement
  • Magnetic Disk - Non-volatile
  • Optical Storage - CDs/DVDs Jukeboxes
  • Tape storage - Backups super-cheap painful to
    access

4
Jim Grays Storage Latency Analogy How Far
Away is the Data?
5
1956 IBM RAMAC 24 platters 100,000 characters
each 5 million characters
6
1979 SEAGATE 5MB
7
1998 SEAGATE 47GB
8
2004 Hitachi 400GB Height (mm) 25.4. Width (mm)
101.6. Depth (mm) 146. Weight (max. g) 700
9
2006 Western Digital 500GB Weight (max. g) 600g
10
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11
Typical Values Diameter 1 inch ? 15
inches Cylinders 100 ?
2000 Surfaces 1 or 2 (Tracks/cyl) 2
(floppies) ? 30 Sector Size 512B ?
50K Capacity 360 KB (old floppy) ?
300 GB
12
Reliability Issues Mean time to failure
(MTTF) 57 to 136 years Given 1000 new disks
with 1,200,000 hours of MTTF, on average one
of them will fail in 1200 hours 50 days.
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