Notes, summaries, assignments, exams, and problems for Computers

Linux System Administration Knowledge Check

I. Processes and System Management Fundamentals

1. The processes are: F.
2. An orphan process: V.
3. The Kill Command: F.
4. The top command: V.
5. For information: V.

II. File System, Commands, and Permissions

Any information or documents: F. The dir command: F. Hidden files: V. If in a line: V. The command ls /etc/f*: V. The /etc/fstab file: F. Even though we have: F. Using the grep command: F. cp -i: F. The mv -r command: F. bzip2: F. To decompress: V. The command passwd: F. To list the contents: F. To mount a directory: F. ln /home/pepe/public: F. The command who: V. The command line root@: F. chmod g+x: F.

III. Networking and Connectivity Configuration

wget -r: V. Network interfaces: V. Any user: F. No user: F. Get... Continue reading "Linux System Administration Knowledge Validation and Command Reference" »

Electronic Communication includes email, electronic newsletters, and video conferencing systems.

Interpersonal Network involves informal discussions with team members and external individuals who may offer valuable insights or visions to aid the team.

Decomposition of the Problem

Decomposition of the problem, also known as partitioning or elaboration, is an activity based on core software requirements analysis. The level of decomposition is not intended to be complete. Instead, it is applied in two main areas: the functionality to be delivered and the process to be used for delivery.

PROCESS: The generic stages characterizing the software process—definition, development, and support—are applicable to all software.

Software Process Models

• Linear

... Continue reading "Software Project Management: Risks and Models" »

Java Programming Fundamentals

Variables and Data Types

• Which of the following options is not a variable? Literal
• A block of related data elements is called a table.
• According to convention, the dollar sign character is never used to start a variable name.
• An object is a software bundle related to its state.
• Using 16-bit Unicode.
• You can use the short data type to save memory in large tables.
• You do not need to assign a value when a field is declared.
• Each item in a table is called an element.
• Parameters are always variables.
• The length of a table is set when the table is created.

Operators and Expressions

• The operator with the highest priority is evaluated before operators with lower priority.
• Operators on the same line have equal priority.
• If the name of

... Continue reading "Java Programming Fundamentals: Key Concepts and Best Practices" »

OSI Model Essentials

The OSI model, developed by ISO, standardizes protocols dominated by TCP/IP and is crucial for network designers. It comprises seven layers for sending commands:

Application Layer

Provides user access to the OSI environment and distributed information services.

Presentation Layer

Ensures application processes are independent of data representation differences.

Session Layer

Manages communication between applications, establishing, managing, and closing connections.

Transport Layer

Ensures secure, transparent data transfer between points, including error recovery and flow control.

Network Layer

Manages switching and transmission techniques, establishing, maintaining, and closing connections at the hardware level.

Data Link Layer

Provides... Continue reading "Understanding the OSI Model: 7 Layers of Network Communication" »

Memory Modules

Small printed circuit boards built on different memory chips:

• DIMM (Dual In-Line Memory Module): Similar to the SIMM, physically larger, and have 168 contacts. They are distinguished by having a notch on both sides and two more in the row of contacts. The mounting of the sockets is different than that of the SIMM. DIMMs are found in 32, 64, 128, 256, 512 MB, and 1, 2 GB capacities.
• DIMM DDR: Has gradually replaced the standard DIMMs. It has a total of 184 pins instead of the 168-pin DIMM of SDRAM. Physically, they resemble the above but have one notch in the row of contacts.
• DIMM DDR2: Has 240 pins and a notch in a different position than DDR DIMMs.
• DIMM DDR3: Also has 240 pins but is neither physically nor electrically compatible

... Continue reading "Types of RAM Modules: DIMM, DDR, RIMM, FB-DIMM, GDDR, SO-DIMM" »

Creating an Effective Home Page

Once you have selected the content and structure of your website, it is crucial to understand how to effectively combine text and images to create an attractive site that draws in visitors. Keep in mind that design is merely a vehicle for presenting your content, which is ultimately what matters most. Both concepts must be balanced. Avoid saying too little with poor execution or having a visually appealing design with meaningless content. You may also encounter pages overloaded with pretty pictures that take minutes to download. A page that takes longer than 15 seconds to load will likely not be very user-friendly. Visitors prefer to go elsewhere.

Reading extensive text on a computer screen is uncomfortable and... Continue reading "Web Page Creation: Design, Structure, and Optimization" »

Common Features of IPC Light Mechanisms

These mechanisms are implemented as a unit and share common features, including:

• All mechanisms have a table whose entries describe their usage. Each table entry has a numerical key chosen by the user.
• Each mechanism has a 'get' call to create a new entry or retrieve an existing one. The parameters of this call include a key and a mask of flags. The kernel searches the table for an entry that matches the provided key.
• If the key is set to IPC_PRIVATE, the kernel occupies the first free entry. Subsequent calls will return this entry until it is released.
• If the IPC_CREAT flag is active in the mask, the kernel creates a new entry if there is no match for the provided key. If both IPC_CREAT and IPC_EXCL flags

... Continue reading "Shared Memory in IPC: Features and Creation" »

Software Applications and Data Handling

Spreadsheet Applications

Leaf is a software application that allows mathematical operations, working with numerical data, making complex calculations with formulas and functions, and generating graphs. In this unit, we will use the spreadsheet applications Excel and Calc.

Spreadsheet Errors

Spreadsheet errors do not tell us whether we made an error in an entry or operation. In Calc, error messages are available as codes. In Excel, the error messages are:

• #####: The cell width cannot display content, or you have used a negative date or time.
• #VALUE!: You have used an incorrect argument type or operation.
• #NAME?: The text of the formula is not recognized.
• #REF!: The cell reference is invalid.
• #N/A: Not available

... Continue reading "Spreadsheet Software Functions and Disk Partitioning Concepts" »