Computer Fundamentals and System Concepts

A retrovirus specifically targets antivirus programs to disable them and avoid detection. A worm spreads automatically across networks, a trojan disguises itself as legitimate software, and 'ghost virus' is not a standard malware classification.

RISC stands for Reduced Instruction Set Computer, a processor design philosophy using simple, fast instructions. The other options are plausible-sounding but invented acronyms that don't correspond to actual computing concepts.

PCMCIA (Personal Computer Memory Card International Association), ISA (Industry Standard Architecture), and EISA (Extended Industry Standard Architecture) are all expansion slot or bus design standards used in computers. PROM (Programmable Read-Only Memory) is a type of memory chip used for storing permanent data, not an expansion slot or bus interface. Therefore, PROM is the correct answer as it does not fit the category of expansion slot/bus design.

A retrovirus is a type of malware that specifically targets antivirus programs, security software, or system defense mechanisms to disable them and avoid detection. A worm is self-replicating malware that spreads across networks. A trojan disguises itself as legitimate software. 'Ghost virus' is not a standard malware classification term.

RISC stands for Reduced Instruction Set Computer, a processor architecture that uses a small, highly optimized set of simple instructions. This contrasts with CISC (Complex Instruction Set Computer) architectures like x86. RISC designs emphasize simplicity and efficiency, allowing for pipelining and faster clock speeds.

The UNDO_POLICY=REQUIRED option in SAS SQL ensures that if any rows in an INSERT or UPDATE operation fail to meet the specified integrity constraint criteria, the entire operation is rolled back and the table is restored to its original state before the operation began. This provides transactional integrity by preventing partial updates. Option C correctly describes this behavior.

In SAS SQL set operations (UNION, INTERSECT, EXCEPT) without keywords like ALL or CORR, columns are matched by position (ordinal) not by name. The columns must have compatible data types but need not have the same name. Column names in the result come from the first table. Therefore, the statement that 'To be overlaid, columns must have the same name' is FALSE, making option C the correct answer.

Option B is correct: the UNIQUE keyword in CREATE INDEX prevents duplicate values in the indexed column. Option A (KEY) is not a valid keyword for enforcing uniqueness. Option C (NODUPS) is not valid SAS syntax. Option D (NODUPKEY) is a SAS dataset option, not a CREATE INDEX keyword.

In the physical layer, a single database table can have multiple aliases with different primary key definitions. This is useful when the same table plays different roles in a dimensional model (e.g., a Date table used for both Order Date and Ship Date). Each alias can define its own primary key context.

The Intel 8085 is an 8-bit microprocessor - its accumulator, ALU, and data bus are all 8-bit wide. The 8086 is a 16-bit processor, while the 80386 and 80486 are 32-bit processors. The question asks for an 8-bit processor, and 8085 is the only correct option among these Intel processors.

UNICS (later UNIX) originally stood for UNiplexed Information and Computing System, a play on Multics (Multiplexed Information and Computing Service). It was not 'UNified', nor is 'UNIX Information and Calculating System' the historically accurate expansion.

Opening email attachments or messages from unknown sources is historically the most common way viruses infect computers. Email remains a primary vector for malware distribution. Installing games from CDs, uploading pictures from phones, or sending emails are not significant virus transmission methods compared to email-based attacks.

Opteron was the first 64-bit microprocessor developed by AMD for servers and workstations, introducing the AMD64 (x86-64) architecture. Athlon was originally a 32-bit processor line (with Athlon 64 released later), iMac is an Apple product, and RISC-9000 is an HP architecture.