WGU D686 OPERATING SYSTEMS FOR
COMPUTER SCIENTISTS OA
CERTIFICATION SCRIPT 2026 QUESTIONS
WITH SOLUTIONS GRADED A+
◍ How many threads can a process have?.
Answer: One or more (can be multiple).
◍ What is a DDoS attack?.
Answer: Distributed Denial-of-Service—multiple systems attack a target,
overwhelming it.
◍ Command Line Interface.
Answer: a user types commands represented by short keywords or
abbreviations or presses special keys on the keyboard to enter data and
instructions
◍ Device Driver.
Answer: An operating system component that provides uniform access to
various devices and manages I/O to those devices. Ensure the device works
on all known operating systems
◍ Status Information.
Answer: A system service. Some programs simply ask the system for the
date, time, amount of available memory or disk space, number of users, or
similar status information.
◍ What is a denial-of-service (DoS) attack?.
Answer: An attack that disrupts system services by overwhelming resources.
◍ Sharing.
Answer: The act of linking the same copy of a module to multiple other
, modules. Sharing improves memory utilization by allowing multiple
processes to share common routines or services (Ex: compilers, editors,
word processors), or common data (Ex: dictionaries). Sharing is possible
under both static and dynamic linking
◍ What is a back door?.
Answer: A hidden way to bypass normal authentication and gain
unauthorized access to a system.
◍ What is a capability list?.
Answer: Specifies which resources a user/process can access.
◍ read-only memory (ROM).
Answer: It's a type of computer storage containing non-volatile, permanent
data that, normally, can only be read, not written to.
◍ Which operating system feature is responsible for selecting a process to
execute?.
Answer: Scheduler
◍ Trapdoor (aka Backdoor).
Answer: Mechanism that bypasses user authentication. Ex: A systems
programmer could modify the login utility to accept a specific user without
requiring a password, thus permitting unauthorized access to the system at a
later time
◍ Global data.
Answer: data items that are automatically available to all modules
throughout the system
◍ What is the difference between a virus and a worm?.
Answer: Virus attaches to files and needs user action; worm spreads
automatically without user intervention.
◍ What is the recommended Linux file system for flash drives?.
Answer: EXT2 (no journaling, less write wear).
◍ What is volatile memory?.
, Answer: Loses data when power is lost (e.g., RAM).
◍ shared code.
Answer: one copy of read only code shared among processes
◍ Shared Memory.
Answer: In interprocess communication, a section of memory shared by
multiple processes and used for message passing.
◍ Which type of computer should be used for hosting web and email services
while maximizing uptime?.
Answer: Server
◍ What is a code-injection attack?.
Answer: Attacker inserts malicious code into a program or system, often
through input fields.
◍ Swapping.
Answer: Temporary removal of a module from memory. The module is
saved on a disk and later moved back to memory. Dynamic relocation is
necessary so that the module can be placed into a different location without
modification.
◍ What is Dropbox?.
Answer: A cloud-based file storage and sharing service.
◍ What is DMA (Direct Memory Access)?.
Answer: Allows devices to transfer data to/from memory without CPU
intervention; used for fast data transfer.
◍ Uses of Embedded Systems as a computing environment.
Answer: -Most prevalent-Real Time-Primitive-Works within time
constraints-Could have an OS or not
◍ Worst-fit.
Answer: Takes the opposite approach from best-fit by always choosing the
largest available hole for any request.
◍ Uses of Server as a computing environment.
, Answer: In general, any computer, no matter the size, that provides
resources to other computers.
◍ What is a Master File Table (MFT)?.
Answer: NTFS metadata table for all files.
◍ How can you access Dropbox?.
Answer: Web browser, desktop app, mobile app.
◍ Fragmentation.
Answer: In the context of a hard disk, is a condition in which the contents of
a single file are stored in different locations on the disk rather than in a
contiguous space
◍ Supervisor Call or Kernel Call.
Answer: Provide the interface between the OS kernel and the higher-level
software.
◍ Locations where firmware can be stored.
Answer: Flash Memory, Read-only memory
◍ What is the difference between stream cipher and block cipher?.
Answer: Stream cipher encrypts data one bit/byte at a time; block cipher
encrypts fixed-size blocks.
◍ What is the main difference between EXT2 and EXT3?.
Answer: EXT3 adds journaling for reliability.
◍ Main difference between trap and interrupt.
Answer: The difference between ____(1) and ____(2) is that a __(1) is
triggered by a user program to invoke OS functionality.An ___(2) is
triggered by a hardware device to allow the processor to execute the
corresponding interrupt handler routine.
◍ What is asymmetric encryption?.
Answer: Uses a public key to encrypt and a private key to decrypt.
◍ Least Recently Used (LRU).
Answer: It selects the page that has not been referenced for the longest time.
COMPUTER SCIENTISTS OA
CERTIFICATION SCRIPT 2026 QUESTIONS
WITH SOLUTIONS GRADED A+
◍ How many threads can a process have?.
Answer: One or more (can be multiple).
◍ What is a DDoS attack?.
Answer: Distributed Denial-of-Service—multiple systems attack a target,
overwhelming it.
◍ Command Line Interface.
Answer: a user types commands represented by short keywords or
abbreviations or presses special keys on the keyboard to enter data and
instructions
◍ Device Driver.
Answer: An operating system component that provides uniform access to
various devices and manages I/O to those devices. Ensure the device works
on all known operating systems
◍ Status Information.
Answer: A system service. Some programs simply ask the system for the
date, time, amount of available memory or disk space, number of users, or
similar status information.
◍ What is a denial-of-service (DoS) attack?.
Answer: An attack that disrupts system services by overwhelming resources.
◍ Sharing.
Answer: The act of linking the same copy of a module to multiple other
, modules. Sharing improves memory utilization by allowing multiple
processes to share common routines or services (Ex: compilers, editors,
word processors), or common data (Ex: dictionaries). Sharing is possible
under both static and dynamic linking
◍ What is a back door?.
Answer: A hidden way to bypass normal authentication and gain
unauthorized access to a system.
◍ What is a capability list?.
Answer: Specifies which resources a user/process can access.
◍ read-only memory (ROM).
Answer: It's a type of computer storage containing non-volatile, permanent
data that, normally, can only be read, not written to.
◍ Which operating system feature is responsible for selecting a process to
execute?.
Answer: Scheduler
◍ Trapdoor (aka Backdoor).
Answer: Mechanism that bypasses user authentication. Ex: A systems
programmer could modify the login utility to accept a specific user without
requiring a password, thus permitting unauthorized access to the system at a
later time
◍ Global data.
Answer: data items that are automatically available to all modules
throughout the system
◍ What is the difference between a virus and a worm?.
Answer: Virus attaches to files and needs user action; worm spreads
automatically without user intervention.
◍ What is the recommended Linux file system for flash drives?.
Answer: EXT2 (no journaling, less write wear).
◍ What is volatile memory?.
, Answer: Loses data when power is lost (e.g., RAM).
◍ shared code.
Answer: one copy of read only code shared among processes
◍ Shared Memory.
Answer: In interprocess communication, a section of memory shared by
multiple processes and used for message passing.
◍ Which type of computer should be used for hosting web and email services
while maximizing uptime?.
Answer: Server
◍ What is a code-injection attack?.
Answer: Attacker inserts malicious code into a program or system, often
through input fields.
◍ Swapping.
Answer: Temporary removal of a module from memory. The module is
saved on a disk and later moved back to memory. Dynamic relocation is
necessary so that the module can be placed into a different location without
modification.
◍ What is Dropbox?.
Answer: A cloud-based file storage and sharing service.
◍ What is DMA (Direct Memory Access)?.
Answer: Allows devices to transfer data to/from memory without CPU
intervention; used for fast data transfer.
◍ Uses of Embedded Systems as a computing environment.
Answer: -Most prevalent-Real Time-Primitive-Works within time
constraints-Could have an OS or not
◍ Worst-fit.
Answer: Takes the opposite approach from best-fit by always choosing the
largest available hole for any request.
◍ Uses of Server as a computing environment.
, Answer: In general, any computer, no matter the size, that provides
resources to other computers.
◍ What is a Master File Table (MFT)?.
Answer: NTFS metadata table for all files.
◍ How can you access Dropbox?.
Answer: Web browser, desktop app, mobile app.
◍ Fragmentation.
Answer: In the context of a hard disk, is a condition in which the contents of
a single file are stored in different locations on the disk rather than in a
contiguous space
◍ Supervisor Call or Kernel Call.
Answer: Provide the interface between the OS kernel and the higher-level
software.
◍ Locations where firmware can be stored.
Answer: Flash Memory, Read-only memory
◍ What is the difference between stream cipher and block cipher?.
Answer: Stream cipher encrypts data one bit/byte at a time; block cipher
encrypts fixed-size blocks.
◍ What is the main difference between EXT2 and EXT3?.
Answer: EXT3 adds journaling for reliability.
◍ Main difference between trap and interrupt.
Answer: The difference between ____(1) and ____(2) is that a __(1) is
triggered by a user program to invoke OS functionality.An ___(2) is
triggered by a hardware device to allow the processor to execute the
corresponding interrupt handler routine.
◍ What is asymmetric encryption?.
Answer: Uses a public key to encrypt and a private key to decrypt.
◍ Least Recently Used (LRU).
Answer: It selects the page that has not been referenced for the longest time.
