True or false. Every word has only one correct spelling and pronunciation.

In Criminal justice, the type of evidence which contradicts a given theory is known as?

irina [24]

Answer:

In general, scientific evidence are the results of scientific tests used to prove or disprove a theory or hypothesis. In criminal cases, scientific evidence is used to help jurors understand and determine the facts of a case. Explanation:

3 0

2 years ago

Olivia wants to change some settings in Outlook. What are the steps she will use to get to that function? open Outlook → File →

Rainbow [258]

Answer:

C.

Explanation:

edg 2020

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2 years ago

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There will be 10 numbers stored contiguously in the computer at location x 7000 . Write a complete LC-3 program, starting at loc

Artist 52 [7]

Answer:

The LC-3 (Little Computer 3) is an ISA definition for a 16-bit computer. Its architecture includes physical memory mapped I/O via a keyboard and display; TRAPs to the operating system for handling service calls; conditional branches on N, Z, and P condition codes; a subroutine call/return mechanism; a minimal set of operation instructions (ADD, AND, and NOT); and various addressing modes for loads and stores (direct, indirect, Base+offset, PC-relative, and an immediate mode for loading effective addresses). Programs written in LC-3 assembler execute out of a 65536 word memory space. All references to memory, from loading instructions to loading and storing register values, pass through the get Mem Adr() function. The hardware/software function of Project 5 is to translate virtual addresses to physical addresses in a restricted memory space. The following is the default, pass-through, MMU code for all memory references by the LC-3 simulator.

unsigned short int get Mem Adr(int va, int rwFlg)

{

unsigned short int pa;

// Warning: Use of system calls that can cause context switches may result in address translation failure

// You should only need to use gittid() once which has already been called for you below. No other syscalls

// are necessary.

TCB* tcb = get TCB();

int task RPT = tcb [gettid()].RPT;

pa = va;

// turn off virtual addressing for system RAM

if (va < 0x3000) return &memory[va];

return &memory[pa];

} // end get MemAdr

Simple OS, Tasks, and the LC-3 Simulator

We introduce into our simple-os a new task that is an lc3 Task. An lc3 Task is a running LC-3 simulator that executes an LC-3 program loaded into the LC-3 memory. The memory for the LC-3 simulator, however, is a single global array. This single global array for memory means that alllc3 Tasks created by the shell use the same memory for their programs. As all LC-3 programs start at address 0x3000 in LC-3, each task overwrites another tasks LC-3 program when the scheduler swaps task. The LC-3 simulator (lc3 Task) invokes the SWAP command every several LC-3 instruction cycles. This swap invocation means the scheduler is going to be swapping LC-3 tasks before the tasks actually complete execution so over writing another LC-3 task's memory in the LC-3 simulator is not a good thing.

You are going to implement virtual memory for the LC-3 simulator so up to 32 LC-3 tasks can be active in the LC-3 simulator memory without corrupting each others data. To implement the virtual memory, we have routed all accesses to LC-3 memory through a get Mem Adr function that is the MMU for the LC-3 simulator. In essence, we now have a single LC-3 simulator with a single unified global memory array yet we provide multi-tasking in the simulator for up to 32 LC-3 programs running in their own private address space using virtual memory.

We are implementing a two level page table for the virtual memory in this programming task. A two level table relies on referring to two page tables both indexed by separate page numbers to complete an address translation from a virtual to a physical address. The first table is referred to as the root page table or RPT for short. The root page table is a fixed static table that always resides in memory. There is exactly one RPT per LC-3 task. Always.

The memory layout for the LC=3 simulator including the system (kernel) area that is always resident and non-paged (i.e., no virtual address translation).

The two figures try to illustrate the situation. The lower figure below demonstrates the use of the two level page table. The RPT resident in non-virtual memory is first referenced to get the address of the second level user page table or (UPT) for short. The right figure in purple and green illustrates the memory layout more precisely. Anything below the address 0x3000 is considered non-virtual. The address space is not paged. The memory in the region 0x2400 through 0x3000 is reserved for the RPTs for up to thirty-two LC-3 tasks. These tables are again always present in memory and are not paged. Accessing any RPT does not require any type of address translation.

The addresses that reside above 0x3000 require an address translation. The memory area is in the virtual address space of the program. This virtual address space means that a UPT belonging to any given task is accessed using a virtual address. You must use the RPT in the system memory to keep track of the correct physical address for the UPT location. Once you have the physical address of the UPT you can complete the address translation by finding the data frame and combining it with the page offset to arrive at your final absolute physical address.

A Two-level page table for virtual memory management.

x7000 123F x7000 0042

x7001 6534 x7001 6534

x7002 300F x7002 300F

x7003 4005 after the program is run, memory x7003 4005

x7004 3F19

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3 years ago

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In the story, what are the song pauses a metaphor for?

-BARSIC- [3]

Answer:

D. The need to slow down more often in life.

4 0

3 years ago

The following SQL statement uses a(n) _____. SELECT P_CODE, P_DESCRIPT, P_PRICE, V_NAME FROM PRODUCT, VENDOR WHERE PRODUCT.V_COD

Trava [24]

Answer:

The answer is c. “old-style” join.

Explanation:

SELECT P_CODE, P_DESCRIPT, P_PRICE, V_NAME

FROM PRODUCT, VENDOR

WHERE PRODUCT.V_CODE = VENDOR.V_CODE;

The SELECT clause represents all the columns to be displayed.

The FROM clause represents the tables which are used to extract the columns.

The WHERE clause shows the common column that exists in both the tables. This represents the old-style join when JOIN keyword was not used.

The tables are joined in two ways.

1. Using JOIN keyword

The syntax for this is given as

SELECT column1, column2

FROM table1 JOIN table2

ON table1.column3 = table2.column3;

This returns all rows from two tables having the same value of common column.

Two tables are taken at a time when JOIN keyword is used.

If more tables are to be used, they are mentioned as follows.

SELECT column1, column2

FROM table1 JOIN table2

ON table1.column3 = table2.column3

JOIN table3

ON table3.column4 = table1.column4

( ON table3.column5 = table2.column5 )

The part in italics shows that the third table can either share the same column with table1 or table2.

The given query can be re-written using JOIN as shown.

SELECT P_CODE, P_DESCRIPT, P_PRICE, V_NAME

FROM PRODUCT JOIN VENDOR

ON PRODUCT.V_CODE = VENDOR.V_CODE;

2. Equating common column in WHERE clause

SELECT column1, column2

FROM table1, table2

WHERE table1.column3 = table2.column3;

This returns all rows from two tables having the same value of the common column.

Here, no keyword is used except the general syntax of the query. ON keyword as shown in the above example is replaced with WHERE.

Tables to be used are mentioned in FROM clause separated by commas.

Tables are joined based on the same column having same values.

Multiple tables can be joined using this style as follows.

SELECT column1, column2

FROM table1, table2, table3, table4

WHERE table1.column3 = table2.column3

AND table3.column5=table1.column5

AND table3.column4 = table2.column4;

5 0

3 years ago