Questões de Concurso Comentadas para cops-uel

Nowadays the relational model is the primary data model for commercial data-processing applications mainly due to its simplicity, which eases the programmer’s job, when compared to earlier data models such as the network model or the hierarchical model.

Regarding the structure of relational databases, match the column 1 with the one 2.

Column 1

(I) Relation.

(II) Tuple. 

(III) Attribute. 

(IV) Table. 

(V) Domain.

Column 2

(A) It refers to a row. 

(B) It refers to permitted values.

(C) It refers to a table.

(D) It refers to a column.

(E) It has a single name.

Choose the alternative with the right association.

A structural problem for digital signatures is that everyone has to agree to trust a central authority that knows everything and is trusted by everyone. The most logical candidates for central authority are the government, the banks, the accountants, and the lawyers. Unfortunately, none of these organizations inspire total confidence in all citizens. Hence, it would be nice if signing documents did not require a trusted authority. Fortunately, Public-key cryptography can make an important contribution to the improvement of digital signature security, allowing person A to send a digital signed message to person B without requiring a central authority.

Considering that person A has the private-key D_A and the public-key E_A and person B has the private-key D_B and public-key E_B, choose the alternative that shows the correct sequence of utilization of the keys when person A signs a message M, sends it to B and B checks he signature.

Consider the following statements about object-oriented programming.

I. Using different names for operations in the same types is called overloading.

II. Overloaded operators are useful to add functions to enable conventional notation.

III. A derived class is said to inherit properties from its base, so the relationship is also called inheritance.

IV. Pointers to functions can be used to provide a simple form of polymorphic routines.

Choose the right alternative.

Some Intel processors provide hardware-assisted virtualization to improve the fundamental flexibility and robustness of traditional software-based virtualization solutions by accelerating key functions of the virtualized platform.

About hardware-assisted virtualization, consider the following statements.

I. It enables the VMM to share I/O devices with several guest OSs at the same time.

II. It speeds up the transfer of platform control between the guest operating systems (OSs) and the virtual machine manager (VMM)/hypervisor.

III. It optimizes the network for virtualization with adapter-based acceleration.

IV. It is used in data centers for disaster recovery, high availability and business continuity, and in desktops to increase flexibility, improve security, and reduce costs.

Choose the correct alternative.

The concept of time sharing was developed to improve resource utilization by allowing multiple users to access a single computer system simultaneously, with each user being given the illusion of having access to a full set of system resources. System virtual machines take this concept one step further by providing a similar illusion for complete systems.

Regarding virtual machines, assign T (true) or F (false) to the following statements

(  ) A system VM environment is capable of supporting multiple system images simultaneously, each running its own operating system.

(  ) Each operating system controls and manages a set of virtualized hardware resources.

(  ) Each virtual resource may or may not have a corresponding physical resource.

(  ) Real resources of the host platform are shared among the guest system VMs, with a layer of hardware.

(  ) Both virtual machines and native systems have the same capabilities.

Choose the alternative that shows, top-down, the correct sequence.