190、The purpose of his recent trip to Hangzhou was to attend a meeting

108、Most operating systems provide a file system, as a file system is an integral part of any modern operating system.Early microcomputer operating systems’ only real task was file management - a fact reflected in their names ( ).Some early operating systems had a separate component for handling file systems which was called a disk operating system.On some microcomputers, the disk operating system was loaded separately from the rest of the operating system.On early operating systems, there was usually support for only one, native, unnamed file system; for example, CP/M supports only its own file system, which might be called “CP/M file system” if needed, but which didn＇t bear any official name at all. Because of this, there needs to be an interface provided by the operating system software between the user and the file system.This interface can be textual ( ) or graphical ( ).If graphical, the metaphor of the folder, containing documents, other files, and nested folders is often used ( ). In a flat file system, there are no subdirectories-everything is stored at the same ( ) level on the media, be it a hard disk, floppy disk, etc.While simple, this system rapidly becomes inefficient as the number of files grows, and makes it difficult for users to organize data into related groups. Like many small systems before it, the original Apple Macintosh featured a flat file system, called Macintosh File System.Its version of Mac OS was unusual in that the file management software ( ) created the illusion of a partially hierarchical filing system on top of MFS.This structure meant that every file on a disk had to have a unique name, even if it appeared to be in a separate folder.MFS was quickly replaced with Hierarchical File System, which supported real directories.(1)、The early microcomputer operating systems’ mainly task is.

107、The main hardcopy output devices are printers and plotters.A printer can print characters.symbols, and usually graphics on paper, Printers are categorized according to whether or not the image produced is formed by physical contact of the print mechanism with the paper.Impact printers make contact; nonimpact printers do not.Impact printers usually form images by pressing an inked ribbon against the paper with a hammer-like mechanism.A letter-quality printer like a typewriter, presses fully formed characters against the ribbon.A dot- matrix printer uses separate pin-like hammers to form characters out of dot patterns.Letter quality printers produce higher quality images than do dot- matrix printers and are generally used for business letters, important memos, and reports.However, letter-quality printers are slower and noisier than dot-matrix printers, and they cannot produce graphics.Common types of impact letter-quality printers are the daisy wheel printer, the thimble printer, and the ball printer.Dot-matrix printer, because they do not print fully formed characters, are more flexible and can be used to print graphics in black or in color. The high-volume output requirements of most large computer installations cannot be satisfied by dot-matrix or letter-quality printers.Large computer systems often use special high-speed printers, called line printers that print a whole line at a time.Three common types of line printers are drum printers, band or belt printers, and chain printers.(5)、What is the main point of this paragraph?

107、The main hardcopy output devices are printers and plotters.A printer can print characters.symbols, and usually graphics on paper, Printers are categorized according to whether or not the image produced is formed by physical contact of the print mechanism with the paper.Impact printers make contact; nonimpact printers do not.Impact printers usually form images by pressing an inked ribbon against the paper with a hammer-like mechanism.A letter-quality printer like a typewriter, presses fully formed characters against the ribbon.A dot- matrix printer uses separate pin-like hammers to form characters out of dot patterns.Letter quality printers produce higher quality images than do dot- matrix printers and are generally used for business letters, important memos, and reports.However, letter-quality printers are slower and noisier than dot-matrix printers, and they cannot produce graphics.Common types of impact letter-quality printers are the daisy wheel printer, the thimble printer, and the ball printer.Dot-matrix printer, because they do not print fully formed characters, are more flexible and can be used to print graphics in black or in color. The high-volume output requirements of most large computer installations cannot be satisfied by dot-matrix or letter-quality printers.Large computer systems often use special high-speed printers, called line printers that print a whole line at a time.Three common types of line printers are drum printers, band or belt printers, and chain printers.(4)、If we want print a business letter, which printer is the best choose that is mentioned in this text?

107、The main hardcopy output devices are printers and plotters.A printer can print characters.symbols, and usually graphics on paper, Printers are categorized according to whether or not the image produced is formed by physical contact of the print mechanism with the paper.Impact printers make contact; nonimpact printers do not.Impact printers usually form images by pressing an inked ribbon against the paper with a hammer-like mechanism.A letter-quality printer like a typewriter, presses fully formed characters against the ribbon.A dot- matrix printer uses separate pin-like hammers to form characters out of dot patterns.Letter quality printers produce higher quality images than do dot- matrix printers and are generally used for business letters, important memos, and reports.However, letter-quality printers are slower and noisier than dot-matrix printers, and they cannot produce graphics.Common types of impact letter-quality printers are the daisy wheel printer, the thimble printer, and the ball printer.Dot-matrix printer, because they do not print fully formed characters, are more flexible and can be used to print graphics in black or in color. The high-volume output requirements of most large computer installations cannot be satisfied by dot-matrix or letter-quality printers.Large computer systems often use special high-speed printers, called line printers that print a whole line at a time.Three common types of line printers are drum printers, band or belt printers, and chain printers.(3)、Which of the following descriptions about the printer is wrong?

107、The main hardcopy output devices are printers and plotters.A printer can print characters.symbols, and usually graphics on paper, Printers are categorized according to whether or not the image produced is formed by physical contact of the print mechanism with the paper.Impact printers make contact; nonimpact printers do not.Impact printers usually form images by pressing an inked ribbon against the paper with a hammer-like mechanism.A letter-quality printer like a typewriter, presses fully formed characters against the ribbon.A dot- matrix printer uses separate pin-like hammers to form characters out of dot patterns.Letter quality printers produce higher quality images than do dot- matrix printers and are generally used for business letters, important memos, and reports.However, letter-quality printers are slower and noisier than dot-matrix printers, and they cannot produce graphics.Common types of impact letter-quality printers are the daisy wheel printer, the thimble printer, and the ball printer.Dot-matrix printer, because they do not print fully formed characters, are more flexible and can be used to print graphics in black or in color. The high-volume output requirements of most large computer installations cannot be satisfied by dot-matrix or letter-quality printers.Large computer systems often use special high-speed printers, called line printers that print a whole line at a time.Three common types of line printers are drum printers, band or belt printers, and chain printers.(2)、How many types of impact letter-quality printers are mentioned in this paragraph?

107、The main hardcopy output devices are printers and plotters.A printer can print characters.symbols, and usually graphics on paper, Printers are categorized according to whether or not the image produced is formed by physical contact of the print mechanism with the paper.Impact printers make contact; nonimpact printers do not.Impact printers usually form images by pressing an inked ribbon against the paper with a hammer-like mechanism.A letter-quality printer like a typewriter, presses fully formed characters against the ribbon.A dot- matrix printer uses separate pin-like hammers to form characters out of dot patterns.Letter quality printers produce higher quality images than do dot- matrix printers and are generally used for business letters, important memos, and reports.However, letter-quality printers are slower and noisier than dot-matrix printers, and they cannot produce graphics.Common types of impact letter-quality printers are the daisy wheel printer, the thimble printer, and the ball printer.Dot-matrix printer, because they do not print fully formed characters, are more flexible and can be used to print graphics in black or in color. The high-volume output requirements of most large computer installations cannot be satisfied by dot-matrix or letter-quality printers.Large computer systems often use special high-speed printers, called line printers that print a whole line at a time.Three common types of line printers are drum printers, band or belt printers, and chain printers.(1)、How many types of Impact printers are mentioned in the second paragraph?

106、10. there were search engines there was a complete list of all web servers.

105、9.It is important to that a dynamic programming approach is only justified if there is some degree of overlap in the subproblems.

104、8.Typographical errors, misplaced cards, and employee apathy could soon erroneous and conflicting data within the various data systems.

103、7.In a typical compromise, an attacker may gain super user privileges for a short duration trivially undertake the above attacks.