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1
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2
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3
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4
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5
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- Invented in 1725 by Basile Bouchon as a medium to hold information used
by looms when weaving complex-patterned fabrics
- Widely used during much of the twentieth century for teletypewriter
communication
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6
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- When the first minicomputers were released, most manufacturers turned to
teletypewriters as a low-cost solution for keyboard input and printer
output
- As a side effect punched tape became a popular medium for low cost
storage
- It was common to find a selection of tapes containing useful programs in
most minicomputer installations.
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7
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- Slow (75 WPM)
- Awkward (Difficult to recoil the tape issuing from the reader)
- Some applications used fan-fold tape which was an improvement
- Fragile (Tape tore easily and was difficult to mend)
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8
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9
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10
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- Herman Hollerith developed punched card data processing technology for
the 1890 US census
- IBM manufactured and marketed a variety of machines for creating,
sorting, and tabulating punched cards, even after expanding into
computers in the late 1950s
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11
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- Punched cards are still in limited use gathering input data for
computers. Recall the debacle in Florida during the 2000 presidential
election
- However they were never (to my knowledge) used as removable storage for
microcomputers
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12
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13
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14
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- Most microcomputers of the late 1970s and early 1980s used cassette tape
for storage of both program software and data
- Tapes could be read or written at a speed of from 500 to 1000 bps
- A 90-minute cassette had a total capacity of approximately 330 kB per
side
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15
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- Users had to fast forward or rewind the tape to the correct spot and
then “read” the contents of the tape into the computer’s RAM
- The first version of the IBM PC of 1981 had a cassette port and a
command in its ROM BASIC programming language to use it
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16
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17
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18
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- In 1967, IBM wanted a way, faster and lighter than tape reels, to load
microcode into their customers’ System/370 mainframes
- Their solution was a read-only 8” diameter plastic disk with a coating
of magnetic material that had a storage capacity of 80 kB and cost only
$5
- In later versions, the storage capacity was increased to 250 kB
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19
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- Because they featured random access to the stored data, they were
considered “high speed” compared to cassette tapes
- But the drives were expensive, typically costing more than the computer
to which they were attached
- The first microcomputer operating system, CP/M, originally shipped on
8″ disks
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20
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21
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22
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- Northstar introduced the 5 1/4-inch floppy in 1977. The originals were
hard sectored diskettes that had ten holes in them. The storage capacity
was only 70 kilobytes. A double density controller released the
following year provided 140 K
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23
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- Beginning in 1979, the 5¼″ format now, thanks to Maxell, available
in a soft sectored version, quickly displaced the 8″ for most
applications and began to make serious incursions into the domination of
cassette tapes
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24
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- Like the 8″ Floppy, the 5¼″ version consisted of a thin
metallic-coated plastic disk encased in a felt-lined paper sleeve
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25
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26
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- The paper sleeve had an oval cutout through which the drive head could
access the information stored on the plastic disk
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27
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28
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- Because of their construction, they were very fragile, easily bent or
creased
- They were also extremely sensitive to heat and magnetic fields
- Placing one on top of a computer or on the dashboard of a car on a sunny
day could cause major data loss
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29
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- On the right side there was a notch called the “write-enable slot”
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30
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31
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- To make the disk read-only, one had to paste a small piece of paper over
the notch
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32
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- These early drives read only one side of the disk, leading to the
popular budget approach of cutting a second write-enable slot and index
hole on the opposite edge of the carrier envelope and flipping it over
to use the other side for additional storage (thus, the "flippy
disk")
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33
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- When first introduced, 5¼″ disks had a maximum storage capacity of
180 kB
- Tandon introduced a double-sided drive in 1980, doubling the capacity to
360 kB
- In 1982 a new "double density" format increased it again, to
720 kB
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34
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- Finally, in 1984, a “high density” version was introduced with a storage
capacity of 1200 kB (1.2 MB)
- Since the IBM AT personal computer, also introduced that year, had a
hard drive that stored a maximum of 10 to 20 MB, the capacity of the
high density 5¼″ floppy was considered quite large
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35
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- For most of the 1980s the 5¼″ floppy drive was the primary storage
device for microcomputers.
- Since many of these micros had no hard drive, the OS was usually booted
from one floppy disk, which was then removed and replaced by another one
containing the application.
- Some machines using two disk drives (typically “A” and “B”) allowed the
user to leave the OS disk in place and simply change the application
disks as needed
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36
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37
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38
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- By the end of the 1980s, the 5¼″ disks had been superseded by the
3½″ disks
- The latter had a number of advantages over the older format, including a
small form factor and a rigid case with a slideable write protect catch
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39
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40
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- The standard version was released by Sony in 1983 with a capacity of 360
kB (the same capacity as the 5¼″ disks of the time)
- In 1986, a 720 kB version was introduced
- A newer "high-density" format, displayed as "HD" on
the disks themselves and storing 1440 kB of data, was introduced in 1987
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41
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- By 1988, they were outselling the 5¼″ version
- The 1.44 MB High Density floppy drive soon became universal on virtually
all PC and Macintosh hardware and remained so for 16 years - until 2004
- In 2004, Dell became the first major personal computer supplier to make
the 3½″ floppy drive an optional extra
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42
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43
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44
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- The Zip drive was a large-capacity removable disk storage system,
introduced by Iomega in late 1994
- Originally it had a capacity of 100 MB, but later versions
increased this to 250 MB and then 750 MB
- The drive was initially sold for just under $200 with one cartridge
included, and additional 100 MB cartridges sold for $20
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45
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- There were many competitors:
- Jaz drive
- Bernoulli Box
- Ditto drive
- LS-120 drive
- EZ 135 Drive
- Orb Drive
- All very similar in construction, cost and capacity
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46
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- They sold well at first because they were seen a relatively inexpensive
substitutes for the hard drives of the day
- But by 1998 these disks had a relatively high cost per megabyte compared
to the falling costs of both hard drives and optical storage media
(CD-RW and DVD±RW)
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47
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- There was also the problem of:
- The Click of Death
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48
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49
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50
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- All the storage devices we’ve talked about so far are Magnetic storage
devices
- That is, they store the information on a metallic surface in the form of
magnetic “dots”
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51
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- On Optical drives, when data are recorded, a laser burns tiny “pits” in
a reflective material on the disk
- The data are read by detecting variations in the intensity of the
reflected light from the media surface
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52
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- Optical recording systems potentially have much greater reliability
- There is a much larger distance between the read/write element and the
moving media and therefore no wear associated with repeated use of the
optical systems
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53
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- The main disadvantages of optical storage when compared to magnetic is
slower random data access.
- This partially comes from the design of the relatively large and heavy
optical heads
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54
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55
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- First introduced in 1997, CD-RWs have a capacity of 645 to 700MB and can
be written to approximately 1,000 times
- They have a “shelf life” of 3 to 5 years
- Despite their relatively low cost, they have not been adopted for
wide-spread use as removable storage devices
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56
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- The process of transferring data to them is much slower than to other
storage devices
- It requires specialized software
- CD-RW disks need to be re-formatted either entirely or "on the
fly" before recording new data
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57
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- They are most useful for temporary short or mid-term backups, and where
an intermediate solution between online and offline storage schemes is
required.
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58
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- DVD-RAM
- DVD-RW
- DVD+RW
- Blu-Ray
- HD DVD
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59
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- DVD-RAM:
- Introduced in 1998
- Single-sided capacity 4.7 GB
- Double-sided capacity 9.4 GB
- Can be accessed just like a hard or floppy disk without any special
software
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60
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- DVD-RAM:
- Long life - without physical damage, data is retained for 30 years
minimum.
- Can be rewritten over 100,000 times (DVD±RW can be rewritten
approximately 1,000 times)
- DVD-RAM media is more expensive than other DVD types (~$9 per disk)
- DVD-RAM writing is slower than DVD+RW and DVD-RW
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61
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- DVD-RW and DVD+RW:
- Mostly Tweedledum and Tweedledee
- DVD-RW introduced by Pioneer in 1999
- DVD+RW introduced by Phillips in 2001
- Both have a capacity of 4.7 GB and record at comparable speeds
- Both have a estimated life of 10 years or 1000 writes
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62
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- DVD-RW and DVD+RW:
- DVD+RW supports random write access, which means that data can be added
and removed without erasing the whole disc and starting over
- Conversely, DVD-RW is more like CD-RW: to change data, one must erase
the whole disc and start over again
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63
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- DVD-RW and DVD+RW:
- Originally the two formats were competitive with one another
- But by 2002 Sony introduced a DVD±RW drive that could read or write in
both formats
- There are still some compatibility problems with older home DVD players
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64
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- DVD-RW and DVD+RW:
- In May 2004, Sony introduced a dual-layer DVD-RW with a capacity of 9
GB
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65
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- Blu-Ray and HD DVD
- Situation similar to VHS vs Betamax
- Blu-Ray (Sony, Panasonic, Samsung, Dell, HP, Philips)
- HD DVD (Toshiba, NEC, Microsoft, LG)
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66
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- Blu-Ray
- Capacity of 50 GB
- Disks and players are more expensive
- Players $900-$1200
- Disks $25-$35
- Got a head start of about 6 months
- HD DVD
- Capacity of 30 GB
- Less costly
- Players $400-$600
- Disks $15-$25
- Has a more recognizable name
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67
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- Now let’s turn back to Magnetic memory...
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68
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69
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70
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71
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- No different in basic technology from ordinary hard drives, just easier
to move around
- Capacities range from 4GB to 20GB
- Powered by the USB port on the host computer
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72
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- The most common are those based on 1” Microdrives
- They aren't much larger than the drive they contain, and often have
retractable USB plugs
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73
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- They are meant to have the same practicality and ease of use of flash
drives (discussed next)
- But they are still based on an actual (albeit micro-sized) hard disk
with moving heads and spinning platters, so they are much less tolerant
of abuse
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74
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- Their principal advantage is that they are transportable, plugging into
any computer via a USB port
- Their principal disadvantages are their fragility and the fact that they
are noticeably slower than an internal hard drive
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75
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76
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- Flash memory is a form of non-volatile computer memory that can be
electrically erased and reprogrammed
- Flash memory costs far less than other forms of non-volatile memory and
therefore has become the dominant technology wherever a significant
amount of non-volatile, solid-state storage is needed
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77
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- Flash memory offers faster read access times and better kinetic shock
resistance than hard disks
- Another allure of flash memory is that when packaged in a “memory card”
it is nearly indestructible by ordinary physical means, being able to
withstand intense pressure and boiling water
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78
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- Examples of applications include digital audio players, digital cameras,
GPS devices and cell phones.
- There are many manufacturers of flash memory devices and almost as many
shapes, sizes and capacities
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79
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80
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- Flash memory can be accessed by the device in which it is contained
- Storing pictures on a digital camera
- Playing music on a MP3 player or iPod
- Displaying maps in a GPS device
- Playing saved messages or ringtones on a cell phone
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81
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- Flash memory can also be accessed by a desktop or laptop computer or by
a printer
- Directly, by connecting the device containing the flash memory to a
computer or printer using a USB connection
- Or indirectly, via...
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82
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83
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84
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85
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- But the really important thing to remember is
- All Flash Memory Devices are the Same Inside
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86
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- Among other things, this means you can:
- Take a bunch of pictures with your digital camera
- Remove the memory card from your camera and put it in your pocket
- Come over to my house
- Plug the memory card into my computer
- Show me the pictures
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87
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- Among other things, this means you can:
- Show up at my house with your mp3 player
- See a new program on my computer of which you’d like to have a copy
- Copy the application software from my computer to your mp3 player
- Return home and copy the software from your mp3 player to your hard
drive
- Install it on your computer
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88
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- Flash memory is also used in USB thumb drives (also called flash drives,
jump drives, pocket drives, handy drives, stick drives, etc), which are
used for general storage and transfer of data between computers.
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89
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90
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91
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92
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93
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94
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95
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96
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97
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- USB thumb drives are compact and easy-to-use devices that are similar in
function to a computer hard drive
- USB thumb drives slip into your pocket, on a lanyard around your neck or
on a keychain for ultimate portable storage
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98
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- A thumb drive consists of a small printed circuit board encased in a
robust plastic or metal casing
- Only the USB connector protrudes from this protection, and is usually
covered by a removable cap
- Thumb drives use a standard type-A USB connection allowing them to be
connected directly to a port on a personal computer
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99
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- To access the data stored in a thumb drive, the drive must be connected
to the computer's USB port
- Thumb drives are active only when powered by a USB computer connection,
and require no other external power source or battery power source
- They are powered using the limited supply afforded by the USB
connection.
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100
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- Currently, memory capacity ranges from 128 megabytes up to 64 gigabytes,
limited only by flash memory densities
- USB Thumb Drives are relatively inexpensive although cost per megabyte
increases rapidly at higher capacities due to the expensive components
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101
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- Based on a recent price check, thumb drives were available in retail
stores and online at $10 for 512MB, $15 for 1GB, $30 for 2GB and $45 for
4 GB
- A 32GB drive could be had for about $400 and a 64GB version was priced
around $1,000
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102
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- They can be used for transporting personal files (just like floppies,
but a lot more capacious)
- Data
- Music
- Pictures
- Video
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103
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104
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105
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106
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107
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108
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109
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- Pocket Gaming without a PSP
- Mame - brings back the arcade and console hits of yesteryear by running
ROM files
- Simply download the application from www.mame.net and unpack it on your
flash drive
- Legally, you must own the original game to download the thumb drive
version of any of the more than 5800 available. Visit www.mameromlinks.com
to get started
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110
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- A 50MB Linux distro that will boot from a thumb drive and allows you to
tinker with the popular open-source operating system without having to
risk modifying your hard drive
- Available as a free download
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111
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- Word-processor
- Spreadsheet
- Web browser
- Email
- Instant Messenger
- Graphics editing and viewing
- MP3, CD Music, and MPEG Player
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112
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- Carry Your Desktop in Your Pocket
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113
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- Synchronizes back to your own PC. Compatible with portable memory
devices including flash drives, smartphones and MP3 players
- $29.99 plus the cost of the flash drive at www.migosoftware.com
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114
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- A thumb drive formatted for the U3 “operating system” by the
manufacturer
- Not significantly more expensive than non-formatted drives
- Requires only ~8MB of space on the thumb drive (plus space for
additional programs and data)
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115
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116
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117
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118
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119
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120
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121
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122
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123
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- With either U3 or PortableApps, you can:
- Plug your UTD into the USB port of any computer anywhere – a friend’s
house, an Internet Café, a hotel business center, an office – anywhere,
and see your own familiar desktop, programs, and data
- Run Portable Firefox or Portable Thunderbird and surf the Web or pick
up email, put the final touches on your document or slide show
presentation with Writer or Impress; play your favorite music or watch
videos
- Remove the UTD at the end of the session and no record of your session
or anything personal remains on the host computer
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124
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- USB thumb drives and other forms of flash memory finally fulfill the
real promise of the digital age:
- Complete freedom and mobility
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125
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Notes
