CompTIA Tech+ (FC0-U71) (FC0-U71) — Questions 901–975

The correct matches are: Table (rows/columns), Primary Key (unique identifier), Foreign Key (link to another table), Query (data request). Common confusions include mixing up primary and foreign keys.

A switch creates a local area network (LAN) by forwarding frames based on MAC addresses, allowing all five computers, two printers, and one server to communicate directly. The router provides network address translation (NAT) and a default gateway for internet access, so connecting the switch to the router enables all devices on the switch to reach the internet. This is the standard small office topology because the switch handles internal traffic efficiently at Layer 2, while the router handles Layer 3 routing and internet connectivity.

Normalization aims to reduce redundancy, enforce data integrity, and eliminate update anomalies. It rarely improves query performance (often may reduce it due to more joins).

Configuring VLANs separates wired and wireless traffic into distinct broadcast domains, reducing the amount of broadcast traffic and collisions that the router's CPU must process. This lowers CPU overhead, which directly addresses the 90% CPU usage causing intermittent drops, without requiring new hardware.

The System process (PID 4) is using the most memory at 44,236 K, as shown in the Memory column of Task Manager. This process represents the Windows kernel and core OS services, and its memory usage is typically high because it manages system resources, drivers, and hardware abstraction. In this exhibit, the Memory column is sorted by usage, and System appears at the top with the highest value.

Full disk encryption (e.g., BitLocker) encrypts the entire drive, making data unreadable without the key.

A trigger can be programmed to check, before an INSERT or UPDATE on the Orders table, whether the new CustomerID exists in the Customers table. If the value is not found, the trigger can roll back the transaction, enforcing referential integrity without using a formal foreign key constraint. This is a valid method in database systems that support procedural logic within triggers.

ProfessorID in Courses is a foreign key; many courses can have the same professor (one-to-many); the primary key of Professors is ProfessorID.

The error indicates that the column 'user_id' does not exist in the 'users' table. The most logical first step is to check the table definition to confirm the actual column names, as the developer may have misspelled the column name or used the wrong case. This avoids unnecessary destructive actions like dropping the table or making incorrect assumptions about case sensitivity.

The OS manages hardware resources and provides services for application software.

Storage types have different technologies: HDD uses magnetic disks, SSD uses flash memory, RAM is volatile. Common mistakes include swapping magnetic and flash, or confusing volatile vs non-volatile.

In Scrum, new work is added to the product backlog and prioritized by the product owner for a future sprint; the current sprint scope is not changed.

When a web application constructs SQL queries by concatenating user input directly, an attacker can inject malicious SQL code into the query. This allows the attacker to manipulate the database, such as by bypassing authentication, retrieving unauthorized data, or executing arbitrary commands. This is the classic definition of SQL injection, which exploits the lack of input sanitization or parameterized queries.

Trial software is time-limited for evaluation before purchase.

Client-server networks are designed to support a variety of client devices, including desktop computers, laptops, and smartphones, which all connect to a centralized server to request resources or services. Option B is correct because the defining characteristic of a client-server network is the presence of a centralized server that manages resources, such as file storage, authentication, or database access, and controls access to those resources for all clients.

A primary key uniquely identifies each row in a table; it must contain unique values and no NULLs.

Virtual machines use virtualized resources: vCPU (virtual CPU), vRAM (virtual RAM), and virtual storage (such as virtual hard disks). Physical USB ports and physical GPU are not virtual resources; they are passed through to the VM if needed.

Ransomware encrypts files for ransom. It is often delivered via a trojan (disguised as legitimate software) that the user inadvertently runs. The other options are incorrect: adware shows ads, spyware collects info, rootkit hides.

Interpreted languages are executed line by line without prior compilation.

The first step in troubleshooting a slow computer is to identify the cause of the performance issue. Task Manager provides real-time data on CPU, memory, disk, and network utilization, allowing you to pinpoint which process or resource is being overused. This diagnostic approach follows the standard troubleshooting methodology of gathering information before making changes.

A 'division by zero' error occurs when a program attempts to divide a number by zero, which is mathematically undefined and typically raises a runtime exception. The most likely cause is unvalidated user input that supplies a zero as the divisor, because the program does not check or sanitize the input before performing the arithmetic operation.

Windows executable installers typically use the .exe extension. .msi is also common for Windows Installer packages, but .exe is the most common for applications. .dmg is for macOS, .deb for Debian-based Linux.

Auditing current permissions (Option B) is the first step in applying least privilege because it identifies exactly which users have excessive rights. Creating RBAC groups (Option C) then allows the analyst to assign permissions based on job functions, ensuring users only have the access necessary to perform their roles. Together, these actions systematically reduce privilege levels without disrupting operations.

A while loop is the correct construct because it repeatedly executes a block of code as long as a specified condition remains true. This is ideal for scenarios where the number of iterations is not known in advance and depends on a dynamic condition, such as waiting for a file to appear or a network response.

Inkjet printers generally produce better color quality for images and photos compared to laser printers.

A UNIQUE constraint ensures that all values in a column or a set of columns are distinct from one another, preventing duplicate entries. This is a standard SQL integrity constraint that enforces data uniqueness at the table level, and it is correctly listed as a valid database integrity constraint.

Adware displays unwanted advertisements, often bundled with free software.

SSDs use flash memory, offering faster speeds and better durability than HDDs due to no moving parts. HDDs are slower and more prone to mechanical failure.

Laser printers are faster and have lower cost per page for high-volume text printing compared to inkjet printers.

Initializing a variable (like sum) to a starting value (0) is a fundamental step in accumulation algorithms. Without this initialization, the sum would contain an undefined or garbage value, leading to incorrect results. This is a standard practice in pseudocode and real programming languages alike.

A Type 1 hypervisor runs directly on hardware and allows multiple VMs with different OSes. It is efficient for server virtualization.

A wireless router with an integrated switch combines a router, a wireless access point, and a multi-port Ethernet switch into a single device. This allows the office to connect all 15 devices wirelessly while sharing the single internet connection, and the integrated switch provides wired ports for devices that may need a stable connection. It is the simplest and most cost-effective solution for a small office requiring easy setup and wireless connectivity.

Bandwidth is the maximum rate at which data can be transferred over a network path, typically measured in bits per second (bps). A lower bandwidth directly limits the throughput of a file transfer, causing it to take longer regardless of other factors. This is the most fundamental constraint on transfer speed, as it defines the pipe size through which all data must flow.

The exhibit shows a firewall rule that blocks outbound traffic on port 445, which is used by SMB (Server Message Block) for file sharing. Since the user is trying to connect to a network share on a remote server, the outbound SMB traffic is being blocked, preventing the connection. This is the most likely cause because SMB relies on port 445 for direct TCP communication, and blocking outbound traffic on this port stops the client from initiating the connection.

Tailgating (or piggybacking) is a physical social engineering attack where an unauthorized person follows an authorized person into a restricted area.

A relative path specifies location relative to the current directory. Absolute path starts from root (e.g., C:\\).

Adobe Photoshop is an example of application software because it is a program designed to perform specific tasks for end users, such as photo editing and graphic design. Application software runs on top of system software (like an operating system) and directly serves user needs, unlike system software which manages hardware or provides a platform for other software.

git commit saves a snapshot of the changes in the local repository.

Identifying the problem is the first step in the CompTIA A+ troubleshooting methodology. Without clearly defining symptoms and scope, subsequent steps lack direction. This step involves gathering information from users, duplicating the issue, and identifying any recent changes to the system.

AND operation: 1 AND 1 = 1, 1 AND 0 = 0, 0 AND 1 = 0, 1 AND 1 = 1. So 1101 AND 1011 = 1001 (binary).

The GPL is a well-known open-source license that allows users to freely use, modify, and distribute software.

Processing large files often causes performance bottlenecks due to excessive I/O operations. Buffered reading reads data into memory in larger blocks, reducing the number of system calls, while processing in chunks prevents memory overload and allows the application to handle data incrementally. This directly addresses the slow performance by minimizing disk access overhead.

A hierarchical database model is most appropriate for storing an organizational chart because it naturally represents parent-child relationships, such as manager-subordinate reporting lines, in a tree-like structure. This model allows each record to have a single parent and multiple children, directly mirroring the one-to-many relationships in a reporting hierarchy.

A password manager securely stores and generates strong, unique passwords for each account, reducing password reuse and improving security.

The query selects ProductName from the Products table where the Price column is greater than 100. According to the exhibit (not shown but implied), only the row with ProductName 'Laptop' has a Price value exceeding 100, so only 'Laptop' is returned. This demonstrates the basic SQL WHERE clause filtering on a numeric column.

MongoDB is a popular document-oriented NoSQL database.

DNS (Domain Name System) is the technology that translates human-readable domain names (like www.example.com) into machine-readable IP addresses (like 192.0.2.1). When a user types a wrong URL, the browser still sends a DNS query to resolve the domain portion of the URL; if the domain is valid but the path is wrong, DNS resolves correctly, but if the domain itself is mistyped, DNS may fail or redirect to a different IP. This resolution is essential for locating the web server on the internet.

The DISTINCT keyword in SQL is used within a SELECT statement to remove duplicate rows from the result set. When a query returns multiple identical rows, DISTINCT filters them out so that only unique combinations of column values are displayed. This directly addresses the user's requirement to eliminate duplicate rows.

Multi-factor authentication requires two or more factors from different categories: something you know (password), something you have (smartphone app generating a code), and something you are (biometric).

AND: 1&1=1, 0&1=0, 1&1=1, 0&0=0 -> 1010.

A foreign key constraint on the CustomerID column in the Orders table ensures referential integrity by requiring that every value entered in that column must match a CustomerID value in the Customers table. This prevents orphan records and maintains consistency between the two tables, which is the standard relational database approach for enforcing such a relationship.

The error message indicates that the application cannot find the entry point for a function in msvcrt.dll, which is a critical system runtime library for C/C++ applications. This typically occurs when the DLL is corrupted, missing, or of an incorrect version, preventing the application from loading necessary functions. Since the error specifically references msvcrt.dll, the most likely cause is that this runtime library is corrupted or missing.

Eliminating redundant data is a core goal of database normalization because it reduces storage requirements and prevents data inconsistencies. By ensuring each piece of data is stored in only one place, you avoid update anomalies that occur when the same fact is recorded in multiple rows or tables. This practice directly supports the second normal form (2NF) and third normal form (3NF) objectives of removing partial and transitive dependencies.

Mobile Device Management (MDM) allows IT administrators to enforce policies, remotely lock, and wipe devices for security.

SSDs are faster, more durable (no moving parts), and consume less power.

GPL and MIT are well-known open-source licenses.

Mobile Device Management (MDM) allows organizations to enforce policies, manage apps, and secure data on mobile devices.

The INSERT statement fails with a constraint violation because the CustomerID column in the Orders table is defined as a foreign key referencing the CustomerID primary key in the Customers table. When a user attempts to insert a row with a CustomerID that does not exist in the Customers table, the relational database management system (RDBMS) enforces referential integrity and rejects the operation, raising a foreign key constraint violation error.

NVMe SSD provides fast storage; HDMI/DisplayPort supports 4K; Wi-Fi 6 provides modern wireless.

Changing the default administrator password is the best practice because default credentials are widely known and easily exploited, providing an attacker with full administrative access to the wireless access point or router. This action directly mitigates unauthorized configuration changes, which is a fundamental security measure. In contrast, the other options either weaken security or have no significant protective effect.

Google Play is the official app store for Android devices.

DELETE removes rows based on a condition or all rows if no WHERE clause is used, but TRUNCATE also removes all rows. However, DELETE is the standard DML command.

Normalization involves splitting tables to reduce redundancy. First normal form (1NF) eliminates repeating groups, second normal form (2NF) removes partial dependencies, and third normal form (3NF) removes transitive dependencies.

PCI Express (PCIe) slots, especially x16, are used for graphics cards.

Disabling SSID broadcast makes the network name invisible in client scans, reducing casual discovery. However, it is a weak security measure because attackers can still detect the SSID using packet sniffing tools like Wireshark or airodump-ng when a client connects. It should be used as a minor deterrent, not a primary security control.

UTF-8 (a Unicode encoding) uses 1 to 4 bytes per character and supports a vast range of characters.

DDR5 is the latest generation of DDR SDRAM, offering higher speeds and lower power consumption compared to DDR4.

A Type 1 hypervisor (bare-metal) runs directly on the hardware, providing better performance and resource allocation for VMs.

Databases support concurrent multi-user access with locking mechanisms, while flat files cannot handle simultaneous writes safely.

The authentication error specifically indicates that the laptop failed to verify its credentials with the access point. Since the wireless adapter is enabled and the SSID is visible, the most common cause is an incorrect pre-shared key (PSK), which prevents the 4-way handshake in WPA2/WPA3 from completing successfully.