SóProvas

ID
1055491
Banca
CESPE / CEBRASPE
Órgão
STF
Ano
2013
Provas
Disciplina
Inglês
Assuntos

Types of operating systems

Real-time
A real-time operating system is a multitasking operating system that aims at executing real-time applications. Real-time operating systems often use specialized scheduling algorithms so that they can achieve a deterministic nature of behavior. The main objective of real-time operating systems is their quick and predictable response to events. They have an event-driven or time-sharing design and often aspects of both. An event-driven system switches between tasks based on their priorities or external events while time-sharing operating systems switch tasks based on clock interrupts.

Multi-user
A multi-user operating system allows multiple users to access a computer system at the same time. Time-sharing systems and Internet servers can be classified as multi-user systems as they enable multiple-user access to a computer through the sharing of time. Single-user operating systems have only one user but may allow multiple programs to run at the same time.

Multi-tasking vs. single-tasking
A multi-tasking operating system allows more than one program to be running at the same time, from the point of view of human time scales. A single-tasking system has only one running program. Multi-tasking can be of two types: pre-emptive and co-operative. In pre-emptive multitasking, the operating system slices the CPU time and dedicates one slot to each of the programs. Unix-like operating systems such as Solaris and Linux support pre-emptive multitasking, as does AmigaOS. Cooperative multitasking is achieved by relying on each process to give time to the other processes in a defined manner. 16-bit versions of Microsoft Windows used cooperative multi-tasking. 32-bit versions of both Windows NT and Win9x, used pre-emptive multi-tasking. Mac OS prior to OS X used to support cooperative multitasking.

Distributed
A distributed operating system manages a group of independent computers and makes them appear to be a single computer. The development of networked computers that could be linked and communicate with each other gave rise to distributed computing. Distributed computations are carried out on more than one machine. When computers in a group work in cooperation, they make a distributed system.


Embedded
Embedded operating systems are designed to be used in embedded computer systems. They are designed to operate on small machines like PDAs with less autonomy. They are able to operate with a limited number of resources. They are very compact and extremely efficient by design. Windows CE and Minix 3 are some examples of embedded operating systems.

Internet: http://en.wikipedia.org (adapted)

Based on the text above, judge the following items from 111 through 116.

Single-user operating systems do not allow the use of a computer by multiple users. Moreover, they do not allow more than one program to run at the same time.

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Comentários


  • "Single-user operating systems do not allow the use of a computer by multiple users. Moreover, they do not allow more than one program to run at the same time."


    No texto (última linha do multi-user): " may allow multiple programs to run at the same time."

  • Single user mode is a mode in which a multiuser computer operating system boots into a single superuser. It is mainly used for maintenance of multi-user environments such as network servers. Some tasks may require exclusive access to shared resources, for example running fsck on a network share. This mode can also be used for security purposes - network services are not run, eliminating the possibility of outside interference. On some systems a lost superuser password can be changed by switching to single user mode, but not asking for the password in such circumstances is viewed as a security vulnerability.

    https://en.wikipedia.org/wiki/Single_user_mode

  • Single-user operating systems have only one user but may allow multiple programs to run at the same time.