History, System Call Procedure, Process Management and UserProperties of Symbian OSHISTORYSymbian wasan operating system for mobile phones made for smartphones. Symbian was initiallycreated as a OS for PDAs in 1998 by Symbian Ltd. Symbian OS runs basically onARM processors but an x86 port also existed but it was never released.
Symbianwas utilized by many cell phone brands, as Samsung, Motorola, Sony Ericsson,Nokia, Fujitsu, Sharp and Mitsubishi. At the end of 2010 it was the mostpopular smartphone OS but it was overtaken by Android. The last update for theSymbian OS was Nokia Belle Feature Pack 2 release on October 2nd,2017. It is written in C++. Symbian OS v6.
0 and 6.1:This was the first version of its series.This was released in 2001 and was first used in Nokia 9210 communicator.
Andalmost 500,000 Symbian phones were shipped in the year 2001 and the followingyear that number increased to a massive 2.1 million phones. Symbian OS 7.0 and 7.0s:This version was released in 2003.
Thisversion was used by Nokia, Motorola, Sony Ericson and FOMA phones in Japan. One million Symbian phones were shippedin the first quarter of 2003, with the rate increasing to one million per monthby the end of 2003. Symbian OS 8.
0 and 8.1:This version was released in 2004. Its mostsignificant advantage was the choice of two different kernels either EKA1 orEKA2. However, EKA2 shipped a bit later than EKA1. EKA1 was used my some of themanufacturers to make it compatible with the devices which used old devicedrivers. Both the kernels looked almost identical in use but they weredifferent internally.
Symbian OS 9.0 and 9.1:Both of these versions did some back-endimprovements not visible to the user. 9.0 was the final version for EKA1. Symbian OS 9.
1 was released in 2005.Major improvements made in this system were security improvements but therewere quite a lot of bugs in this version. Symbian OS 9.2, 9.3 and 9.5: These versions improved memorymanagement, WIFI support and language support. Application launch up speed wassaid to be 75% much faster. NokiaBelle (Symbian OS 10.
1):Released on 24August 2011, this was considered the last update for Symbian. It addedimprovements to the UI through pull-down status/notification bar, near fieldcommunication (NFC), re-sizable home screen and widget support. SYSTEM CALL · The System Calls process is dealt with the aidof active objects. · The developers noticed that the weight of thethreads which were currently waiting for the call in the ready queue affectedall the other threads in the system.
· The active objects allow the OS to handle thesystem calls rather than the process handling it itself. This is done usingsingle scheduler· The process of system call happens in a waythat active objects signals OS and suspends itself. When the system callcompletes, the suspended process is woken up and it executes as function hadreturned with the data. · The active object can’t call a functiondirectly and expect a return value. It must call a special function which setsup the system call and returns immediately. PROCESS MANAGEMENT The objective of any scheduling strategyis to expand CPU utilization and throughput while limiting turnaround time,waiting time, and response time.
Symbian OS is a real-time system and itutilizes a static, monotonic scheduling strategy, augmented by time slices. MonotonicScheduling:It arranges forms with the briefest due timefirst and the presentation of time cuts implies that procedures with a similardue time (or no due time) can be assigned time cuts and scheduling utilizing apriority-scheduling scheme. There are 64 levels of priority in Symbian OS. Akey to soft real-time performance is predictable execution time.
Thereare several important characteristics that must be predictable including:• Latencytimes: an important benchmark is the latency of handling interrupts: Thetime from an interrupt to a user thread and from an interrupt to a kernelthread.• Thetime to move threads between queues and the CPU: Manipulating schedulingqueues: For example, moving processes to and from the ready queue – must bebounded.• Thetime to get information about processes: For example, the time it takes tofind the highest priority thread in the ready state.USERPROPERTIESEvery operating system provides severalfeatures and specific characteristics from which the user can benefit andfacilitate him/her.
These properties are called as user properties. They helpthe consumer or the user in performing the task efficiently and quickly and inturn it saves the user’s time because the user does not have to wait needlesslyfor these jobs to complete so all in all it benefits the user.Several user properties which the Symbian OSprovides to its users are:· Batchprocessing· Spooling· Interactivity· Multitasking· Real TimeSystem· Multiprogramming· DistributedEnvironment