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schepotkina [342]
3 years ago
15

A set of blocks contains blocks of heights 1,2, and 4 centimeters. Imagine constructing towers of piling blocks of different hei

ghts directly on top of one another. (A tower of height 6 cm could be obtained using six 1-cm blocks, three 2-cm blocks, one 2-cm block with one 4-cm block on top... etc) Let t be the number of ways to construct a tower of height n cm using blocks from the st ( assume an unlimited supply of blocks of each size).
Required:
Find a recurrence relation for t1,t2,t3...
Computers and Technology
1 answer:
SashulF [63]3 years ago
5 0

Answer:

In studies about new medicines, researchers usually give one group of patients the medicine that is designed to treat an illness. They give another group of patients a placebo, which is taken the same way as the medicine but does not actually contain the ingredients of any medicine. Different medicines are tested in different experiments, but the placebos usually contain the same non-medical ingredients. If both groups of patients are healed, then researchers cannot be sure whether the medicine caused improvement, but if the group given the medicine is healed while the group given the placebo remains ill, researchers can conclude that the medicine causes the illness to go away.

In medical experiments, which group receives placebos?

the experimental group

the control group

both the experimental and control groups

neither the experimental nor control group

Explanation:

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2 Write<br>a program to and area of<br>4<br>walls. A = 2h (l+b)​
Zanzabum

Answer:

ADGH AVFH VVBLA FDHLAVRGLBHSRGLHFSgh HGK g gH G avoshhbv so bhsf vhbfsb gfsb gb gh g hhow gw

Explanation:

eehhfhsghOhrrbfghedhchggfgsbbfbhdhfhehyfnfnhhsh

3 0
3 years ago
The first query is computationally less expensive than the second query. (Assume no indexes exist on release_date.) Query 1: SEL
sdas [7]

Answer:

false

Explanation:

The term 'computationally expensive' means that a given mathematical function, code or an algorithm has high computational complexity. In addition, the mathematical function or algorithm will require several steps and procedures to be completed. Based on this, the statement made in this question is not true.

7 0
3 years ago
The data-linking feature that allows Internet users to skip directly from a highlighted word to a related file in another comput
tamaranim1 [39]

Answer:

Hypertext

Explanation:

According to my experience on information technology, I can say that based on the information provided within the question the term being mentioned is called Hypertext. Like described in the question this term refers to a software system which shows as a highlighted piece of text that allows a user to immediately be taken to another system with information associated with the highlighted text that was clicked.

If you have any more questions feel free to ask away at Brainly.

5 0
3 years ago
Read 2 more answers
Convert the following four unsigned binary numbers to decimal and show your work:
Ber [7]

Answer:

23 ,21,10,63,13

Explanation:

We have to convert binary to decimal

10111 corresponding decimal number is

1\times 2^4+0\times 2^3+1\times 2^2+1\times 2^1+1\times 2^0=23

10101 corresponding decimal number is

1\times 2^4+0\times 2^3+1\times 2^2+0\times 2^1+1\times 2^0==21

01010 corresponding decimal number is

0\times 2^4+1\times 2^3+0\times 2^2+1\times 2^1+0\times 2^0=10

111111 corresponding decimal number is

1\times 2^5+1\times 2^4+1\times 2^3+1\times 2^2+1\times 2^1+1\times 2^0=63

001111 corresponding decimal number is

0\times 2^5+0\times 2^4+1\times 2^3+1\times 2^2+1\times 2^1+1\times 2^0=13

7 0
3 years ago
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

7 0
3 years ago
Read 2 more answers
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