In this chapter, we introduce many concepts associated with multithreaded computer systems, including a discussion of the APIs for the Pthreads, Windows, and Java thread libraries. We look at a number of issues related to multithreaded programming and its effect on the design of operating systems.
Finally, we explore how the Windows and Linux operating systems support threads at the kernel level. A thread is a basic unit of CPU utilization; it comprises a thread ID, a program counter, a register set, and a stack. It shares with other threads belonging to the same process its code section, data section, and other operating-system resources, such as open files and signals.
A traditional or heavyweight process has a single thread of control. If a process has multiple threads of control, it can perform Skip to main content. Password protect the screensaver. Secure your wireless network. Secure your backup tapes. First of all, many pieces of information about you can be learned by diligent hackers.
Items such as your name, the names of your children and other personal information should not be used. To be strong, it is best if your password contains characters from three of the following four categories : English uppercase characters a through z. English lowercase characters a through z. Base 10 digits 0 through 9. Non-alphabetic characters for example,! Set up the operating system so that the system login screen does not identify the computer system by name or function until after login is complete.
Unauthorized personnel do not need to know the identity of machines unless they need to use them. For example, the modification of a file can trigger an audit entry that shows the action that was performed, the associated user account, and the date and time of the action. Success audit or failure audit. User rights include log on rights and privileges. Logon rights control who is authorized to log on to a computer and how they can log on. Privileges control access to computer and domain resources An example of a logon right is the ability to log on to a computer locally.
An example of a privilege is the ability to edit a document. Both types of user rights are assigned by administrators to individual users or groups as part of the security settings for the computer. Hacker use the latest security hole to break into a system and work backward from there until they find and open door that give them full access.
Windows update features or automatic update keep the system up to date. Users of the products may be notified by e-mail or obtain information about current hotfixes at a software vendor's Web site and download the hotfixes they wish to apply. Keeping up with patches as they are released saves the enduser time and provides maximum security. Patches require the system to be shut Hotfixes are applied directly while the down, then you must download the systems are still alive. Patches brings many changes Hotfixes are usually small changes to the software.
In most cases, block all ports that are not exclusively required by these services. This is tricky, because you can easily block yourself from services you need. For hardening activities to be most successful should : Do hardening activities before the system is connected to the network to avoid attacks. Base configuration on the least-privilege model: the system should grant access only to the degree necessary for proper functionality. Similarly, users should be allowed only the minimum set of access rights they need.
Bastille is a set of Perl scripts that run as an interactive program, asking questions for each step of the hardening process. The scripts explain each step well, enabling you to understand what security measures will be introduced by any changes you make and why. The program can also log commands and arguments entered by specified system users. Sudo was first released to the public in the summer of , and Todd Miller of Courtesan Consulting currently maintains the program and distributes it freely under a BSD -style license.
Open navigation menu. Close suggestions Search Search. User Settings. Skip carousel. Carousel Previous. Carousel Next. What is Scribd? Explore Ebooks. Bestsellers Editors' Picks All Ebooks. Explore Audiobooks. Bestsellers Editors' Picks All audiobooks.
Explore Magazines. Editors' Picks All magazines. Explore Podcasts All podcasts. Difficulty Beginner Intermediate Advanced. Explore Documents. Did you find this document useful?
0コメント