Assignment 1 – COS 3721
UNISA
UNIQUE NUMBER…………………
STUDENT NUMBER ……………….
, Question 1 – Based on Chapter 1 of SGG
1.1 What is the purpose of interrupts? How does an interrupt differ from a trap? Can
traps be generated intentionally by a user program? If so, for what purpose?
Answer: An interrupt is a hardware-generated change-of-flow within the system. An interrupt
handler is summoned to deal with the cause of the interrupt; control is then returned to the
interrupted context and instruction. A trap is a software-generated interrupt. An interrupt can be
used to signal the completion of an I/O to obviate the need for device polling. A trap can be used
to call operating system routines or to catch arithmetic errors.
1.2 Describe some of the challenges of designing operating systems for mobile devices
compared with designing operating systems for traditional PCs.
Besides a core kernel, middleware must be designed in mobile operating systems to
support a set of software frameworks that provide additional services to application
developers.
Different from using a physical keyboard and mouse, mobile devices need to
features a touch screen and let user interact with the system by pressing and swiping
fingers across the screen.
Mobile operating system must balance the performance with the battery life
Mobile operating system must have a good support for external peripheral devices
like GPS, HDMI which is essential for mobile devices.
Mobile operating system must consider the limited resources since the mobile
devices are much smaller compared with PC.
The mobile devices are more and more related to people's privacy, so the security of
the operating system for the mobile devices counts even more than the traditional
PCs and harder to prevent malicious code and access.
1.3 Identify several advantages and several disadvantages of open-source operating
systems. Include the types of people who would find each aspect to be an advantage or
a disadvantage.
Answer
UNISA
UNIQUE NUMBER…………………
STUDENT NUMBER ……………….
, Question 1 – Based on Chapter 1 of SGG
1.1 What is the purpose of interrupts? How does an interrupt differ from a trap? Can
traps be generated intentionally by a user program? If so, for what purpose?
Answer: An interrupt is a hardware-generated change-of-flow within the system. An interrupt
handler is summoned to deal with the cause of the interrupt; control is then returned to the
interrupted context and instruction. A trap is a software-generated interrupt. An interrupt can be
used to signal the completion of an I/O to obviate the need for device polling. A trap can be used
to call operating system routines or to catch arithmetic errors.
1.2 Describe some of the challenges of designing operating systems for mobile devices
compared with designing operating systems for traditional PCs.
Besides a core kernel, middleware must be designed in mobile operating systems to
support a set of software frameworks that provide additional services to application
developers.
Different from using a physical keyboard and mouse, mobile devices need to
features a touch screen and let user interact with the system by pressing and swiping
fingers across the screen.
Mobile operating system must balance the performance with the battery life
Mobile operating system must have a good support for external peripheral devices
like GPS, HDMI which is essential for mobile devices.
Mobile operating system must consider the limited resources since the mobile
devices are much smaller compared with PC.
The mobile devices are more and more related to people's privacy, so the security of
the operating system for the mobile devices counts even more than the traditional
PCs and harder to prevent malicious code and access.
1.3 Identify several advantages and several disadvantages of open-source operating
systems. Include the types of people who would find each aspect to be an advantage or
a disadvantage.
Answer
