Computer Systems Architecture
Lesson 8
Secondary Management
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SA 8- 0
Computer Systems Architecture
LESSON OVERVIEW
 Introduction to secondary storage
Evolution of secondary storage
Preparation of disks for use
File systems
Introduction of drives to OS
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Computer Systems Architecture
Three Main Storage Structures
Primary
Secondary
Tertiary
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Computer Systems Architecture
Primary Storage
Registers
Caches
The system’s main memory
These are the storage areas that the CPU
can access directly.
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Computer Systems Architecture
Secondary Storage_1
Magnetic Disks
These are used as extensions of the system
memory because they can hold large
quantities of data and can retain it
permanently, unlike the system memory.
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Computer Systems Architecture
Secondary Storage_2
The secondary storage level is an important
aspect of computer design because it allows
for programs and data to be permanently
stored when the computer is powered down.
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Computer Systems Architecture
Secondary Storage_3
The control and management of secondary
storage devices, specifically magnetic disks
by the operating system and by the machine
itself will be considered.
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Computer Systems Architecture
Tertiary Storage
Devices that use removable media
Tape drives
Floppy disks
CD-ROMs
These aren’t considered as secondary storage
because of their slow speed when compared to
magnetic disks.
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Computer Systems Architecture
Preparing Of Disks For Use
Low Level Formatting
Partitioning
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Computer Systems Architecture
Low Level Formatting
Sectors
Tracks
Cylinders
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Computer Systems Architecture
Sectors
Header
Data Area
Trailer
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Computer Systems Architecture
Header
The header contains configuration data used
to synchronize the read heads with the data,
an address field to identify the sector, and a
checksum that validates the header.
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Computer Systems Architecture
Data Area
The data simply contains
the block of data.
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Computer Systems Architecture
Trailer
The trailer has checksum
or error correction
information, used to
detect medium defects.
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Computer Systems Architecture
File System
Basic file system
File organization module
Logical file system
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Computer Systems Architecture
Basic File System_1
It is closest component of the file system to
the hardware.
Its responsibility is to issue commands to the
device drivers of the disk, such as retrieving a
particular block of data.
It doesn’t know about the individual files on
the disk.
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Computer Systems Architecture
Basic File System_2
It only has to worry about communicating
with the disk controller.
It doesn’t change much between different file
systems, as it doesn’t deal with the
organization of data, which is what really
differentiates various file systems.
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Computer Systems Architecture
File Organization Module
It does keep track of the files on the
disk, as well as where they are
located on disk.
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Computer Systems Architecture
Logical File System
It provides the interface between the operating
system and the real meat of the file system,
the previously discussed file organization
module.
It is where the operating system and user
processes can make system calls request file
operations, without knowing anything about
the layout, location, or anything else about the
disk.
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Computer Systems Architecture
Introduction Of Drives To OS
Bootstrap loader
Master Boot Record (MBR)
BIOS
Power On Self Test (POST)
Initial Program Load (IPL) table
Plug eN Play (PnP) Devices
BIOS Aware IPL Devices (BAID)
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Computer Systems Architecture
General Abstraction Layout
in Linux
Kernel
Kernel I/O Subsystem
Drivers for Each Device
Individual Devices
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