the presentation on mAc os is here . i just made a presentation file about the android OS

2. Presented By:
Luneeva Prajapati(760320)
Madan Acharya(760321)
Mehul Rawat(760322)
Nijjal kashyapati(760323)
Oman Neupane(760324)
Prajwal Mahat(760326)
Priyanka Nepal(760327)
Puspan Gautam(760328)
Mac Operating System

3. Agendas:
 Introduction
 History and background.
 Different version of Mac os
 Memory management
 Process Management
 Pros and cons of MAC os

4. Mac os
 Mac os is a series of graphical user interface –
based operating systems developed by Apple Inc.
for their Macintosh line of computer systems.
 Mac OS was designed only to run on Apple
computers.
 In 1984,Apple introduced the Macintosh PC with
the Macintosh Operating system.
 Apple names it’s OS as “Mac OS”,beginning in
1997.

5. Mac OS X
History
1990
2004
February 1994 – Apple announces the beginning of Copland
August 1996 – Apple abandons Copland project
December 1996 – Apple purchases NeXT for $430 million
March 2001 – Apple releases Mac OS X
September 2001 – Apple releases Mac OS 10,1
August 2002 – Apple releases Mac OS 10.2
October 2003 – Apple releases Mac OS 10.3 and the rest is
history.

6. Mac OS X
Background
Aqua
Darwin
Quartz OpenGL QuickTime
Carbon Cocoa Java
• Darwin
– Open Source
– Mach 3.0
– BSD core services

7. • The first Mac was introduced
by Apple’s then-chairman
Steve Jobs was the first
successful personal
computer to feature a
mouse and a Graphical User
Interface(GUI).
• The Mac OS could be easily
distinguished from Other
Operating systems because
it was the only Os with a full
GUI.
• These releases could only
run one program at a time
which could later run
multiple programs.

9. • Aqua interface
development
• 2D and 3D
graphics support
• It featured water
theme
• Due to graphics
improvement
cheetah become
slow and new mac
os is released.
Mac os Cheetah

10. • Simplified CD and
DVD burning
• New features in
Finder
• More extensive
printer support.
Mac os Puma

11. • It added search to
finder.
• MPEG-4 support for
quicktime.
• Range of privacy
features were made
• Accessibility API
(universal Access)
apps were made
Mac os Jaguar

12. • Meet Safari was
introduced as first
web browser made
by Apple
• 150+ new features
including Font
Book,Xcode
enhancements and
more.
Mac os Panther

13. Mac Os Tiger
• It shocked
executives at
Microsoft by
offering a number
of features such as
fast file searching
and improved
graphics
processing,
acomplete built in
dictionary

14. Mac os Leopard
• Apple advertised
that mac os x
leopard has 300+
new features,
including
ichat,Dashboard
enhancements,Dicti
onary could now
search wikipedia
etc.

15. Mac os snow leopard
• Snow leopard
included many
refinements to the
user interface and
New wallapapers

16. Mac os lion
• Launchpad,
multitouch
gestures and
natural
scrolling was
introduced

17. Mac os mountain lion
• Apps like
Notes,Remainders
and Messages
arrive in Mac.
• Notification center
with on screen
banners
comunicating
updates.

18. Mac os Ventura
• Useful Message
Features
• Mail App Features
• Shared Tab Groups
• Passkeys
• Continuity Camera
• Face Time Handoff
• Focus Filters
• Stage Manager
• Lockdown Mode

19. Kernal progamming
 The kernel is the heart of Mac os
 Responsible for resource allocation storage
and printer management
 Uses system calls for ease by programmers

20. Multitasking and Users
• A Mac os system can support up to 100 users
,each concurrently running a different set of
programs
• Processes can communicate with each other
while remaining entirely separate

21. Hierarchial File system
• Provides a structured and secure file system
• Files are stored in hierachical system.

22. Mac OS X
Processor Modes & Privileged Instructions
• Supervisor Mode – allows execution of privileged instructions
and access to privileged registers
– Swapper (PID = 0) – switches processes from main memory to
secondary storage
– PageDaemon (PID = 2) – converts addresses to support the virtual
memory subsystem
• User Mode - The processor mode that forbids execution of
privileged instructions and access to privileged registers. Any
attempt to do so will result in a privilege violation exception.
– Init (PID = 1) – spawns processes for remote terminals; changes run
levels; can assume role of parent for orphaned process

23. Mac OS X
Allowable Process States
Process states for FreeBSD 4.4
• SIDL: Process is partially created
• SRUN: Process is runnable
• SSLEEP: Process is awaiting event
• SSTOP: Process is stopped (by signal or parent
process)
• SZOMB: Process is partially terminated (waiting
for parent process to collect status)

24. Mac OS X
Memory Management
5 Basic Mach Abstractions
• Task
• Thread
• Port
• Message
• Memory Object
Basic VM Operations
• allocate a region of virtual memory on a page boundary,
• deallocate a region of virtual memory,
• set the protection status of a region of virtual memory,
• specify the inheritance of a region of virtual memory and
• create and manage a memory object that can then be mapped into the
address space of another task.

25. Mac OS X
Memory Management (cont.)
Four basic memory management data structures are used in
Mach:
1. the resident page table - a table used to keep track of
information about machine independent pages
2. the address map - a doubly linked list of map entries, each of
which describes a mapping from a range of addresses to a
region of a memory object
3. the memory object - a unit of backing storage managed by the
kernel or a user task and
4. the pmap - a machine dependent memory mapping data
structure (i.e., a hardware defined physical address map).

26. Mac OS X
File Management
File related system calls
Virtual File System (VFS)
UFS HFS+ NFS
UDP
Disk Network
The Darwin kernel implements a Virtual File
System (VFS) that translates a file-related
system call into the matching call for the
appropriate file system.

27. Mac OS X
Threads
• Threads are scheduled to run preemptively or, with symmetric multiprocessing,
concurrently. Threading models built on top of the kernel’s can, however, use
various synchronization mechanisms to present cooperative threading behavior.
• The kernel environment of Mac OS X, specifically Mach, provides the fundamental
thread support. Mach maintains the register state of its threads and schedules
them preemptively in relation to one another. In the case of symmetric
multiprocessing, the kernel can preemptively schedule threads concurrently, one
on each processor. The client API for Mach threads is implemented in the System
framework.
Mach Threads
Posix Threads
Multiprocessing
Services (Carbon)
Thread Manager
(Carbon)
NSThread
(Cocoa)
java.lang.Thread

28. Mac OS X
Scheduling
• Marriage of FreeBSD and Mach
• Uses a priority scheduling algorithm combined with a
time quantum
• Priorities are stored in the PCB and range from -20 to
20 with higher values indicating lower level priority
• “Pzero” refers to a priority variable of 0
• Reschedules every tenth of a second and recomputes
priorities once every second

29. Mac OS X
Scheduling
• No preemption in Mac OS X scheduling
• Task will relinquish CPU after time quantum or when
it must wait for an I/O completion
• Process feedback – priorities change dynamically
based on wait time and amount of time that the
process has had the processor
• Feedback prevents starvation

30. Layers of Mac Os
• The OS consists of
layers that build on top
of each other to handle
more sophisticated
technology.
• The lower the level the
more specialized the
service
• Layer 3,core service is
where memory
management takes
place.

31. The core services layer
• Responsible for
implementing most low
level features
• These features are
included in core
Foundation Framework
• The foundation
framework is built off
higher level features.
• Cocoa uses foundation
framework and
application kit to
implement various
services including
memory management.

32. Virtual Memory
• The virtual memory system used in Mac OS is a descendant of
mach VM.
• Works through idea of physical memory being a cache for virtual
memory.
• VM objects get cached with system pages(RAM)
• Each page is then represented in given address space by map entry
• When a virtual memoryobject is duplicated, it results in creation of
shadow object.
• Initially the shadow object is empty,but when a page is
modified,the contents of parent object get copied into shadow
object
• To then read data from page,the system looks for copy of the page
in the shadow object and if one exists its used,if no object is found
the system uses original parent copy

33. Paging Out Process
• Move any pages that were not recently touched
from active to inactive.
• If a page in the inactive list is not recently
touched ,it finds the page’s VM object.
• The VM object’s paper attempts to write the
page out to the backing store.
• If it succeeds, the kernel frees the physical
memory occupied by the page and move in to
free list.

34. Universal Page lists(UPLs)
• It is type of data structure
that is used when
communicating with a
virtual memory system.
• They have multiple uses
surrounding memory
manipulation
• Changing the behaviour
of pages-
caching,mapping,permissi
ons etc
• Pushing and pulling data
from virtual memory
objects.

35. Paging in Process
• Get pages either from backing store or files containing page
data.
• Memory acccess fault occurs when code tries to access data at
virtual address that is not mapped to physical memory
• Soft Faults
• Page of the referenced address is resident in physical memory
• Page not mapped into the address space of process.
• Hard Faults
• Page of the referenced address is not in physical memory but
is swapped out to backing store
• Also known as page fault.

36. Page lists in the kernel
Active List
• Currently mapped into
memory/have been recently
accessed
Inactive List
• Resident in physical memory but
have not been accessed recently.
• Contains valid data but may be
removed from memory.
Free list
• Physical memory that are not
associated with any address space of
vm object.
• Available for immediate use by any
process that needs them.

37. Advantages of Mac Os
• Easy to use
• Integration with Apple and other Products
• Mac OS can run windows at the same time
• Reliability
• Design

38. Disadvantages of Mac OS
• Gaming
• Price
• Fewer Software Options
• Cannot be upgraded/customized

39. Mac OS X
Future Outlook
“We are betting our future on Mac OS X.” –Steve Jobs
Avie Tevanian, Chief Software Technology Officer at Apple,
explained Mac OS X was the platform of the future: “We built
Mac OS X hoping that it will last 15 to 20 years. I hope it
does,” he joked. “I can’t go through this again.”