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51 Cards in this Set
- Front
- Back
What is temporary storage, high speed memory, immediately accessible to CPU?
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Registers (buffers)
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What are resources live in memory called?
Provide process resources that it requests. Process table keeps list of these. |
Stack
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What holds different condition bits such as whether CPU should be working in User Mode (problem state) or privileged mode (kernel or supervisor mode)?
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Program Status Word (PSW)
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What are Busses? List 2 kinds of busses.
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commute instructions to memory
Data buses - moves data Address buses - used for input/output or identify areas of memory to read from/write to 32 bit and 64 bit refer to width of the bus - more data bits per clock cycle |
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What is the name of the type of RAM in which data must be continually and dynamically refreshed so bits don't disappear?
Cheap and slow |
Dynamic RAM (DRAM)
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What is the name of the type of RAM which hold bits in memory cells without capacitors? Requires more transistors than DRAM. Faster but takes more space
Fast and expensive |
Static RAM (SRAM)
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Type of RAM that is faster than DRAM because can capture next block of data while first is being sent to CPU
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Extended data out DRAM (EDO DRAM)
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Type of RAM that builds upon EDO DRAM. Can send more data at once
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Burst EDO DRAM (BEDO DRAM)
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What kind of I/O device works with data on fixed sized blocks each with own unique address? Disc drive is an example
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Block Device
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What kind of I/O device works with streams of characters without any fixed sizes. Not addressable. A printer, network interface or mouse are examples.
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Character devices
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What kind of I/O device signals interrupt the controller indicating it is done? Device may have to wait.
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Interrupts
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What kind of recovery continues to function despite failure?
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Fault tolerant
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What kind of recovery is it when program execution is terminated and system protected from compromise when hardware or software failure occurs?
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Fail safe
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What kind of recovery allows for non-critical processing to be terminated when failure occurs?
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Fail soft or resilient
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What kind of recovery is it when the machine switches to hot backup?
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Failover
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What does this describe:
Total combination of protection mechanisms within the computer system. Includes hardware, software and firmware. Enforce rules of how subjects and objects interact Originated from the Orange Book |
Trusted Computer Base (TCB)
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What are 4 functions of the TCB?
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1) process activation
2) execution domain switching (when a process needs to call upon a process in a higher protection ring) 3) memory protection 4) I/O operations |
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What is an abstract machine that mediates all access subjects have to objects?
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Reference Monitor
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What is the difference between a security policy and a security model?
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Security policy defines abstract goals and security model provides the how to
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What operates in the security environment at the highest level of classification of the information within the computer. In other words, all users on that system must have clearance to access the info on that system.
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Single State Machine
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What type of security models are interested in the snapshot of the system at a moment in time. Many activities can alter state (state transitions). If something unsafe happens, system must save itself. Error message, reboot, freeze.
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State Machine Model
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What type of security model:
Describes strict layers of subjects and objects and defines clear rules that allow or disallow interactions Provides upper bound and lower bound of authorized access for subjects Uses security clearance and labels |
Multi level lattice models
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What type of security model has one to one relationships between subjects and objects?
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Matrix models
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What type of security model help ensure that high level actions (inputs) do not determine what low level users can see (outputs)?
Actions that take place at a higher security level do not affect or interfere with actions at a lower level |
Noninterference models
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What type of security model is not as concerned with subject to object relationship?
How data is allowed or not allowed between objects |
Information flow models
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What is a covert channel?
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A way for an entity to receive info in unauthorized way
Caused by: Improper oversight in development Improper implementation of access controls Existence of shared resource between two entities |
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What are the three rules for Bell LaPadula?
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1. The simple security rule - subject cannot read to a higher security level - no read up
2. *-property rule - subject cannot write to lower security level - no write down 3. Strong star property rule - can only read and write to equal classification. |
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What are the three rules for the Biba model?
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1. Simple integrity axiom - subject cannot read data from lower integrity level - no read down
2. *-integrity axiom - subject cannot write data to a higher integrity level - no write up 3. Invocation property - cannot request service (invoke) to subjects of a higher integrity |
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Is Clark Wilson an Integrity Model or Confidentiality Model?
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Integrity model.
Meets all three goals of integrity 1. Subjects can access objects only through authorized programs (access triple) 2. Separation of duties is enforced 3. Auditing is required |
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Describe the Brewer and Nash Model.
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AKA Chinese Wall model
Protect against conflicts of interest Based on information flow model |
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What are the 4 levels of TCSEC?
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A - Verified Protection
B - Mandatory Protection C - Discretionary Protection D - Minimal Protection |
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Which evaluation criteria is used in Europe?
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ITSEC
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Which evaluation criteria is the Orange Book?
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TCSEC
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What is certification?
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comprehensive technical evaluation of the security components and their compliance for the purpose of accreditation.
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What is accreditation
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formal acceptance of the adequacy of a systems security and functionality
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What are the three rules of Integrity?
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1. Subjects can access objects only through authorized programs (access triple)
2. Separation of duties is enforced 3. Auditing is required |
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What are the three Integrity goals?
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1. Preventing unauthorised users from making any modifications
2. Preventing authorised users from making unauthorised modifications 3. Maintaining internal and external consistency |
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What is the Access Triple?
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Subject and object are oriented by introducing a third access element - programs - resulting in what is called an access triple, which prevents unauthorized users from modifying data or programs
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What is Abstraction?
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Finding commonality between objects and exploiting to make objects simpler to manage.
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What are control units?
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manages and synchronizes the system while instructions being executed. Fetches and interprets code
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What is Pipelining?
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Combines steps of different instructions.
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What are Complex-Instruction-Set-Computer (CISC)?
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Performs many operations per instruction
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What are Reduced-Instruction-Set-Computer (RISC)?
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Simpler instructions using fewer cycles
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What is a Scalar processor?
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execute one instruction at a time
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What is a Superscalar processor?
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enables concurrent execution of multiple instructions
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What is Electrically Erasable ROM (EEPROM)?
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Flash memory, can be written. More modern form of EPROM
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What is Direct (absolute) Addressing?
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CPU addresses memory by directly specifying the address
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What is Register Direct Addressing?
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CPU addresses memory by directly specifying the address the registers within a CPU
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What is Register indirect addressing?
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CPU addresses memory by addressing the register for the data's address in main memory
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What is Indexed addressing?
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CPU addresses memory by using an index register
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What is Indirect addressing?
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CPU addresses memory by addressing the desired location of the program in memory
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