During the first plan of Windows, one of the objectives was to give 'gadget freedom'. Gadget freedom really intends that a similar program ought to have the option to work utilizing various screens, consoles and printers without alteration to the program. Windows deals with the equipment, permitting the software engineer to focus on the actual program. Assuming that you have at any point needed to refresh the code of a MS-DOS program for the most recent printer, plotter, video show, or console, you will perceive gadget freedom as a tremendous benefit for the designer. Windows programs don't send information straightforwardly to the screen or printer. A Windows program knows where (screen/printer) its yield is being sent. Be that as it may, it doesn't have the foggiest idea how it would be sent there, neither does it need to try to know this. This is since Windows utilizes a norm and reliable method for sending the result to screen/printer. This standard way utilizes an element called Gadget Context, or essentially a DC. Different DC's are related with various gadgets. For instance, a screen DC is related with a screen, a printer DC is related with a printer, and so on. Any drawing that we do utilizing the screen DC is coordinated to the screen. Likewise, any drawing done utilizing the printer DC is coordinated to the printer. In this way, the main thing that changes from attracting to screen what's more, attracting to printer is the DC that is utilized. A windows program acquires a handle (ID an incentive) for the screen or printer's DC. The result information is shipped off the screen/printer utilizing its DC, and afterward Windows and the Device Driver for the gadget takes care of sending it to the genuine equipment. The upside of utilizing the DC is that the designs and message orders that we send utilizing the DC are generally something very similar, paying little heed to where the actual result is appearing. The piece of Windows that changes over the Windows designs work calls to the genuine orders shipped off the equipment is the GDI, or Designs Device Interface. The GDI is a program record called GDI32.DLL and is put away in the Windows System index. The Drawing to a window includes taking care of the WM_PAINT message. This message is created at whatever point the client region of the window should be redrawn. This redrawing would be expected in the accompanying circumstances: (a) When the Window is shown interestingly. (b) When the window is limited and afterward augmented. (c) When some part of the window is covered by another window and the covered window is excused. (d) When the size of the window changes on extending its limits. (e) When the window is hauled out of the screen and afterward carried once more into the screen. Would a WM_PAINT message be produced when the cursor is hauled in the window? No. For this situation the window saves the region covered by the cursor and reestablishes it when the cursor moves to another position. At the point when the switch-case structure inside WndProc( ) sees that as the message ID passed to WndProc( ) is WM_PAINT, it calls the work OnPaint( ). Inside OnPaint( ) we have called the API work BeginPaint( ). This capacity acquires a handle to the gadget setting. Moreover it likewise fills the PAINTSTRUCT structure with data about the region of the window which should be repainted. In conclusion it eliminates WM_PAINT from the message line. In the wake of acquiring the gadget setting handle, the control enters a circle. Inside the circle we have shown "Hi Windows" in three various text styles. Each time through the circle we have arrangement a LOGFONT structure f. This construction is utilized to show the textual style properties like textual style name, textual style tallness, italic or ordinary, and so on. Note that notwithstanding these there are other textual style properties that might be arrangement. The properties that we have not arrangement on the up and up are all introduced to 0. When the textual style properties have been arrangement we have called the CreateFontIndirect( ) API capacity to make the textual style

l. (2pts) In order to ensure efcient usage of a server, it is necessary to estimate the mean number of concurrent users. According to records, the sample mean and sample standard deviation of number of concurrent users at 100 randomly selected times is 37.7 and 9.2, respectively. Construct a 90% condence interval for the mean number of concurrent users. 2. (2pts) To assess the accuracy of a laboratory scale, a standard weight that is known to weigh 1 gram is repeatedly weighed 4 times. The resulting measurements (in grams) are: 0.95, 1.02, 1.01, 0.98. Assume that the weighing's by the scale when the true weight is 1 gram are normally distributed with mean {1. Use these data to compute a 95% condence interval for ,u. 1. Concurrency vs parallelism: 1. Define Concurrency? 2. Define parallelism? 3. Is it possible to have concurrency but not parallelism? Explain Il. Using Amdahl's Law, calculate the speedup gain of an application that has a 60 percent parallel component for: 1. two processing cores 2. four processing cores