Secondary Storage (Hard Disk ; Floppy Disk ; Zip Disk ;etc ) Lecture -11

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notified by our channel so now we are
going to start our topic is second gen
story of devices we are going through
this that is a secondary storage devices
you already learn about it magnetic of
magnetic tape and now we came here now
magnetic this we already learn the
mechanism of magnetic house how it does
work now in this session we will learn
about the various type of magnitude is a
believer okay so now we are going to
start our new topic magnetic disk our
magnetic sorry this is not a magnetic
tape act not a magnetic tape it is a
magnetic disk okay so over magnetic disk
is divided into two part floppy disks
and hard disk so first of all we will
learn about what is for properties after
that we will learn about hardest and
your heart is also
in various type which is Zip disk this
pack and Winchester dis all these things
we will get to know so now we are going
to proceed to our first type of magnetic
disk which is floppy disk okay basically
floppy disk is a round flat piece of
flexible plastic disc coating with
magnetic oxide I already explained you
that your magnet it is is a round coated
this but in your picture you can't even
see this because the this is encased in
this plastic cover so you are not able
to see this disk but here this is inside
this properties and which is obviously
round in shape and flat piece of
flexible plastic disk coated with
magnetic oxide Yoda's is coated with
witness material magnetic oxide now next
point so called because they are made of
plastic plates which can be bent so what
is been that it is made by flexible
plastic plate which can be banned and
also known as floppies or diskette we
also call it a floppy disk as a floppies
or diskettes next point is plastic disk
is can encased in a square plastic
jacket use your plastic disk air book is
may engage with a square plastic jacket
cover that gives handling protection and
this cover will gives the what it gives
handling protection to the disk surface
you cannot even see your disk here so
that your disk is protected in a plastic
and case jacket okay there are two type
of floppy disks in use today which is
first of all five one and 1/4 inch
diskette and second was a third and a
half inch disk a what is the 5 and of a
1/4
this inched escape means whose diameter
is you know that your disc is like that
so this is your call diameter this is
the that is why it is called 1 sorry 5 1
and a 4 1/2 1 and a 4 inch disc a why so
because its diameter is 5 1 and a 4 inch
it is encased in a square flexible wanly
jacket actually the jacket which is in
which it is covered is is a very
flexible windy jacket you can band it ok
and your three and a half inches sketch
whose diameter is three and a half inch
is encased in a square hard plastic this
kind of diskette is placed in cased with
a hard plastic jacket not a windy jacket
which can be bang ok next point is most
popular and it excessive this type of
secondary device is very popular and in
excellent pensive means it is such if in
price so it is in expensive secondary
storage medium used in in spawned
computer in your computer systems your
laptop nowadays we are not using it but
in a older days floppies are very very
popular secondary storage device a few
people not even seen that one floppy
disk now we came to have a second type
of magnetic disk which is called hard
disk what about it first of all first
point is round flat piece of rigid
matter your floppy disk is made by
plastic material but this is made by
rigid met with a better okay frequently
aluminum normally this is mostly made by
aluminum type of metal disc coated with
magnet oxide this kind of this also
coated with rich material magnetic oxide
okay next point is coming many sizes
your heart is come in many sizes ranging
from 1 to 14 inch diameter okay and your
heart is is
divided into three categories also which
is chip justice packet winchester dis
okay next point primary online I already
told you what is offline that you want
to keep record all your implies data is
try kind of offline story and banking
processor or your ticket booking
procedure is all online kind of
procedure though so it is a primarily
online secondary storage device for most
computer system primarily primarily by
means means in your almost in all
computer you seem hardest ok you know
that your computer have a hard disk but
if either you don't have a optical disks
you don't have a magnetic tape it will
be ok but in your computer there with
like RAM and ROM they're hard is also in
your computer you can buy according to
your choice according to your
requirement at how big in size how much
data it can stow your hard is this will
be divided decided by you and you can
select that one kind of hard disk where
your most of all most of your most of
what it is that it will always in your
computer available hard is always
available in your computer so it is a
primary ok definitely it will be on your
computer and our online secondary
storage device for most computer system
now we came to the different types of
hard disk first is zip or we call it
born all it is what we call it barnali
disk this is the I already put our
picture of this disk now going to first
part point of zip this using the single
hardest means in your zip dish there is
only a one single hard disk fatter and
caged in a plastic cartridge ok next
point
this trys may be portable or fixed type
means in which drive you insert your zip
this it may be portable or fixed time is
it is already built in your computer or
you are tensed is by outside and after
that you inserted your zip disks into it
and work on it okay so it is depends
that you want it fist or portable means
want to attach it or from your from the
outside okay
next point fixed type is a part of
computer system I already told you about
what is fixed type and portable now it
is explained again that fixed type Drive
is a part of the computer means it is
already at engineer computer permanently
connected to it okay and what is the
portable type whatever type can be
carried to a computer system means it is
it can be carried to current computer to
another computer connected to it you
connect that one drive to your computer
for a Jewish duration of use and then
can be disconnected and taken away when
the work is done you can disconnect your
display and whenever your work is done
next point of the disk is this your zip
this can be easily inserted or removed
from a zip drive just as which insert or
remove floppy disk or floppy disk drive
okay it is very easy just like your CD
and CD driver it is also like this
defensive driver okay that you inserted
you just as if dis and after working you
can remove your zip disks again okay now
we came to our next type of hard disk
which is dispatch this fix pack actually
have a container and in this can channel
you can see in the pic that there is a
lots of magnetic disks are here one
after that other okay and it means if
you seen that it has a larger store
is why so because you can see in a
picture there there are so many hotties
are in one encased container okay so it
can is two very large amount of data
okay and this container is inserted in
your hard disk drive and I know your
work is then you just put it on a site
from the driver and you can it means it
is a portable kind of thing okay now we
are going to learn about it first point
use multiple two or more hard disk means
it has at least two or more heartless
platter mounted on a single central
shaft you can see that it is a shaft and
in this two or more you can also many
maybe tan on more this are encased okay
second point this choice have a separate
read or write head actually for each
your each disk there is a separate read
or write head I already told you that
this is your head and it your disk is
move like that and it will read the data
from your disk
okay so this drive have a separate read
or write hat each ear your and this pack
has seven disk then it will have seven
days read or write head or if you have a
dentist this this in your dispatch then
definitely there will be ten read or
write hat okay so this die have a
separate read/write head for each usable
disk surface the upper and lower first
of all this is the case that first and
the lower part is not used for first
upper half the topmost is and the lower
surface of the bottom most just is not
used why so if you see in your book this
is your book okay you never write a data
anything on your first page and even you
never write anything on your last fish
why so because by carrying your book
from one place to another most of the
time
your first phase get damaged okay it can
be peel it off or it can be get get
dirty so that is why for a protection we
never write anything when our first and
last year same like that the uppermost
part of your disk we never just drive
and never read or write anything on it
seemed like that on the lower part this
driver never read or write anything on
it okay now we are going to one next
point this car of removal your disk is
removable means whenever you are task is
done you can removed it from your
destroy interchange a work means when if
your data is stored in all 310 this and
you want to store more data then what
will happen you just remove one your dis
pack and insert another dis pack in the
district and again is started you are
storing data okay so it is a removable
or interchangeable type in the sense
that they have to be mounted on the disk
I before they can be used okay and can
be removed and kept offline when not in
use means whenever your ductwork is done
you can kept off this distract from your
drive and keep it up in your shell false
okay now the last type of your hard disk
is winchester disk okay you can see in
this photograph your the this seemed
just like a despite was there a simple
similar not simple but there is some
difference between this pack and
Winchester days first of all it all it
also has so many discs here you can see
that four discs out here okay but what
is the difference between this pack and
Winchester this here you can see that
your dispatch have a driver even it
means that it comes with the driver also
okay you don't need to carry it and you
cannot increase or decrease the size of
your disk means if it has a four
this then it means it is whether it will
be have a four-disc you cannot make
increase means you cannot make more four
more five another disc also inserted on
this dispatch so it is not possible and
you can see that it has a special read
and write and driver at already it is
available here so it comes with a whole
pack with this driver and disc and in
this is a there are also another defense
that you that this driver can also write
or read data in the upper part and the
lower part why so because you have you
never ever you can say that we never
ever carry out this disk from one place
to another place okay so the damages
will never be happen here so there is we
can write data or per part and the lower
part - now we are going to points of
Winchester this first of all use
multiple here you can say see in the pic
that we use multiple to a more hard disk
platter mounted on a single central
shaft okay next point hottest platter
and the disk driver are still together
you can see that this driver and hard is
sealed together in a pack okay in a
content emission-free container and
cannot be separated from each other you
cannot separate your disk driver and
disk separate okay it is combinely here
and we you will have to use it together
okay now the next point is for the same
number of disk
winchester dis have a larger storage Phi
so capacity than that dispatch here you
are this is saying that Winchester this
has a larger space capacity then display
if you see that the previous one this
pack I already explained about you that
this pack in this pack you can increase
the disk number of this if
suppose five days you can add more
three-disc also but in Winchester days
it is not possible if it is a five days
then it will be five always okay
the but in this point it is saying that
for the same number of this but if you
have a same number of this means you
don't you are not adding these three
days in the disk pack this is your
Winchester SiC disk okay so if you are
not increasing the size of the dispatch
then the storage capacity of Winchester
days is Mukul greater than dispatch why
so because I already told you the upper
part you can write on the upper and the
lower part which is not possible in this
pack okay upper and lower part is left
and cover okay all the surface here I
already this discusses tight on it that
all the surface of that of all this are
used for the data recording which is not
possible in its disk pack okay and the
next point is they employ means they use
much greater precision of data recording
result in greater data recording density
here is data recording destory a density
is greater than a dispatch okay now we
came here the advantages of magnetic
this magnitude is means all floppy disk
hard disk and your hardest types which
is Zip disk dis pack and winchester disk
this all comes in your magnetic disks
over on hill again came the advantages
of magnetic disk first of all first or
advantages more suitable than magnetic
tapes for a wider range of application
because they support direct access data
we already known that that magnet it is
a sequential device and direct access
devices whom is magnetic tape and other
when optical design memory
storage devices so this is a the
magnitude distance rider we use by via
so because it has a direct axis okay we
can access data from anywhere from the
memory I already told you that I can
access any from anywhere for my memory
okay next point random access property
means you can access randomly from
anywhere this is called the random
access property enables that to be used
simultaneous I maintain Sui multiple
user as a shared device suppose this is
your memory I already give it to you to
example that this is your memory okay
and each in each cell there is a data
one user want our data which is here and
one user want data which is in this cell
and once user Warren data which is here
if I will use magnetic tape you already
know that in magnetic tape data is a
sequential way okay so if a person need
a data one person here a data of this
cell and once or for the person need a
data from this they both have to go from
this way okay first even first one date
and user will also access then when data
and second one will also able to access
then would add up whether it is usable
for second one user or not but this is
not case in a direct access device so
here you can see that for a direct
access random access characteristic
multiple user can access same cement
liceman that means at the same time
simultaneously means same time at the
same time you get multiple user can
access data because they don't know do
not consider about this cell what is
stored in this cells or what is the
store in this set and same like that
this one user the user 3 will not be
considered this one set up and this one
cells also okay
so multiple users can access or share
the device your memory a tape is not
suitable for such type of users due to
sequential access I already turned that
even our second user will go through
this path so we he he will be able to X
access this one data also okay so in
sequential access this will be not
possible now the third one advantage of
magnetic disk is except for the fixed
eye pins gestures only if you screw your
Winchester disk you here you cannot
increase or decrease the number of disks
in Winchester is but in all of the zip
disk or this pack or your crop it is you
can make more and more disk okay this is
possible so the storage capacity of
other magnetic disses virtually
unlimited why so because you can
increase number of disk okay
as many as this can be used for the
storing very large data set due to their
low cost and high decoding densities the
cost per bit of storage low for magnetic
disk I already told you that how you
will recognize the cost of orbit may be
hard disk um syllabary
a thousand suppose in thousand but the
recording capacity has a very large
amount I already told you it is greater
than hundred GB so you can imagine that
the cost per bit to store a data is very
low okay now we came to next advantage
of magnetic disk an additional cost
benefit is that additional cost when if
it is that magnetic disk can be erased
and you reused okay like your RAM sorry
wrong or other ready devices you already
talked about it previous lecture is that
key there we can erase or you reuse
penny type floppy disk and zip decks are
connect a compact and lighting bank wait
if you I seen in your previous slides
that floppy disk is very small in size
zip it is also so they are compact and
light in weight has they are easy
to handle a store next example very
large amount of data can be stored in a
small storage space you can store a very
large amount of data in this kind of
magnetic disk now next year advantages
are except for the fixed type winchester
disk means excluding your VIN Chester
described the storage capacity of other
magnetic disks is virtually unlimited as
many as just can be used for storing
very large data set okay next point is
due to their low cost because it has a
low cost and high data recording density
the cost per bit is low for magnetic
disk I think so we it on these three
points already covered in the previous
site so don't need to go through this
with again sorry
ok now came here very large amount of
data can be stored in a small storage
space
this was also covered we have covered so
now go to this point that the data
transfer data data are also read for a
magnitude this system is normally higher
than a tape system ok what this means
that your data transfer it means to data
access from the disk is very high so in
compare of magnetic tape okay this is
next our next advantage and after that
magnet it is a less one River to data
corruption due to care less Hanley if
you are not carrying this very carefully
even though your data will not get
corrected so easily okay whether you
burn it or break it down this is an
another method better but otherwise your
heart is never get damaged so easily
okay and for so they weren't able to
data correction due to careless handling
or unfavorable temperature
and humidity condition that magnet it is
I already told you that in magnetic
tapes if there is so much humidity
because it is made by plastic ribbon so
your plastic ribbon can be attached to
each other so they can be damaged so
easily
but it is not happening your magnetic
disk okay
now came to the limitations of magnetic
discs first of all for Winchester discs
we cannot increase or decrease re
increase or decrease the sizes this one
is the main limitation for Winchester
days at this crash or driver flee here
if you adjust as it is because it comes
with the disk driver and if you are
discretion or your driver get failed
often resulting loss of entire restored
data because whatever the data is stored
in your Winchester days you can never be
able to access it again okay which is
not easy to recover the lost data
it is not easy means it may be possible
to recover the data but not so easy you
not so easily you can recover the data
okay next limitations sometime of types
of magnitude disks such as disk pack and
Winchester disks are not so easily
portable you can see in the photographs
that year this back and Winchester's is
in and so many discs are test unit so it
is not so easy to carry out from one
place to another so it is not easy to
portable like make magnetic tapes you
magnet it is it small in size so they
are forever but this pack and Winchester
Isaac is discount big in size so it is
not possible to carry out from one place
to another so they are not portable okay
next limitation of magnetic disk is on a
cost per bit basis if you consider for a
cost per bit basis the cost of magnetic
disk is low but the cost of magnetic
tape is even lower okay I already told
this that cost per bit is no but if you
consider as a magnetic tape then the
then magnetic tape is
we'll be more lower than magnet it is
Phi so I already R that your magnet it
is normally coming around twenty to
forty rupees so they are so low in price
that that's why the cost per bit will be
much lower than magnetic disk okay next
your limitation of magnet addresses must
be stored dust free environment you must
and store your magnet it is in a disk
fear dust free environment
now the uses where you can use your
magnet it is so a magnitude is first
point is for application that are based
on random data processing where you want
to rent dimly access your data in that
kind of application you can use magnet
it is okay next uses where you can use
as a shared online secondary storage
device okay where you can will be
multiple user can share up your
secondary storage device online here
there you can use magnet it is
winchester dis and dis packs are often
used for this purpose okay because they
have several days in a one pack okay
next uses where they can be used as a
backup device you can store data for a
backup in this device so as a backup
device or all offline for of iron
storage of data floppy disk zip disks
and these specs are often used for this
purpose okay for backup
you can use also and for transferring of
data if you want to transfer your data
and program from one computer to another
that are not linked together then you
can store the information of program in
your dysbiotic this and carry out with
to another computer and insert in the
destroyer and now the data or you
program will be available available to
you and in the computer which is not
connected to your computer - okay now
here the
magnetic discs and their types all is
done now we came to our next secondary
direct access storage device which is
called optical tease okay now first of
all we will learn what is optical do
this because it is also a round platter
disk then what is the difference between
magnet it is saying optical is we are
going to see in here now read the first
point consists of a circular disk it is
also a circular disk which is coated
with a thin metal or some other material
that is highly reflected okay they are
in the magnitude is it is coated with
the magnetized of magnetizable thing
okay magnet oxide I think so and this
this one thing is coated on your disk
but in optical disk it is not like that
it is coated with a thin matter or some
other material that is highly reflective
okay they're in your magnitude is there
is a driver to read it write the data
but here in optical days there is a
technology use which is for laser beam
technology is used for recording or
leading reading of data on the disk in
your V CD in your DVD in all these kind
of stuff even in your laptop nowadays
you when you insert a DS in your CD
there is not a any driver of any or you
can say we row right head there is a
technique instance which is called laser
beam whenever a laser beam is reflected
in your CD whatever the data is stored
there it will be redone by the laser
beam similarly like that if you want to
write anything your CD the laser beam
stuck on this surface and will burn that
area okay and store the information
through laser beam technique okay so now
we came to our next point also known as
laser disc we are also call about
optical days as a laser disc or optical
laser it is
due to the use of laser beam technology
okay
why so because we use laser beam
technology next point to to we are
promising random access medium for
high-capacity secondary stories okay it
is a very promising random access device
to store a very high capacity secondary
storage okay because it can store
extremely large amount it can store
extremely large amount of data in a
limited space if you consider your CDs
yes it is have a very large our very
large amount to store in it okay so they
are very promising in storing category
okay now we came to my next point
has one law is pirated in your magnetic
disk if you remember your disk is has
several tracks like that okay but in
your optical disk there is not only one
track like that which is go like easy
spiral like your spring okay swing like
that you can see in this picture that it
started from outer circle and now I
started to inner circle so there is a
one loss track okay not so many luck
track there is only a one track so has
one log spiral track which is start at
outer edge it means it is start from
here okay now which will start from here
and I have in the inner here okay so has
one long spiral track which is start at
the outer edge and is power inward the
center okay next point is track is
divided into equal size sector yojo your
track is divided into equal size or
sector again you will divide your tracks
like that that this is sector this is
sector this is sector this is your
sector okay so same amount of size of
sector divided your track next with
optical disk each sector has the same
length
in optical discs each sector is the same
length regardless of whether it is
located near whether it is located near
or away from the disk Center next point
rotation speed of disk your rotation
speed of disk must vary inversely with
the radius actually it is a random
access device but it is not like that
because it is a spiral way of track I
already explained in the diagram here
the beam start from here and it will be
travels like that and whenever it got
the data it will access suppose your
data is there then it will exist this
one data okay so it work like a
sequential access but the mechanism is
very fast so you'd ever ever realize
that it is working like a sequential
accesses is working like a direct Texas
if you seen your CD if your cds are like
music CD and you want to listen your CD
the song which is on number position 150
ssin so you just press that you want to
listen the hundred and fifty ssin song
but it is not it will directly play this
one song for you okay but you never ever
seen that if your CDs start rotating
very fastly to reach that one case okay
so basically is work like a sequential
essence but because it is very fast to
access the data so you never realize
that it is accessing data like a
sequential way so this also come in a
direct with excess device because it
will not take so much trying to access
the data which is stored here or here
okay next point lead to slower data
access time because if your data is so
invert location so it will take some
times so it leads to slower 8xs time for
larger access time is for optical disks
and magnetic disk because in magnitude
you can read out eye data from anywhere
here also possible but the this will
rotate to reach over there so it will
take some some nanosecond more time
so here excess time will become much
greater larger okay now the next point
of optical disease use laser beam
technology what technology is useless it
used laser beam technology for reading
or IT data and now next point is has no
mechanical read or write excess term it
has no Mechanica excess arm engine like
your magnetic disc see there is a driver
and a arms which have a rear oh right
head but there is a no mechanism is used
here so this kind of mechanism also not
using your optical disk okay
so here we have finished our mechanism
which is used in your optical disk in
our next lecture we will get to know
that how many type of optical disks are
available and other secondary storage
devices use French driver memory card we
will also learn about those kind of
devices you never lost and the next
video lecture of memory secondary memory
device so here is the end of her lecture
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