一种手工恢复文件的方法

一般来说,恢复文件的方法是这样的: 1)打开文件目录登记表,找到该文件对应的目录登记项,将其中第一个字节由E5H改回原来的字符。 2)从目录登记项中获取该文件的起始簇号和文件长度。从起始簇号出发自动或手工在文件分配表(FAT)中恢复出被删除文件的簇号链。 该方法隐含着待恢复文件同时满足下面三个条件:     

《拷贝特大文件的方法》的改进

《电脑》一九九三年第二期刊登一文《拷贝特大文件的方法》,其程序对特大文件的保存带来了方便,但在机器上运行后发现有两点不足:第一是分割速度太慢;其次就是分割后的最后一个文件总是要多一个字节,由此,在DOS下用COPY/B文件+文件+……的方法合起来的文件无法比较是否与原文件相同。本人在TurboC2.0环境下,编制了一个CUT.C程序(程序清单附后),在微模式下编译成CUT.EXE,再用DOS系统提供的EXE2BIN转换成CUT.COM文件。其使用方法: C>CUT Output file Length:这时再输入以比特为单位的长度,然后程序就以这个长度一直把原文件分割完为止。合并文件方法:     

恢复软磁盘文件的方法

Norton Utility是一个非常实用的应用程序,笔者通过文献的启发,成功地恢复了软盘上读写不出来的全部文件。1 软盘文件的恢复 要恢复文件的软盘,是用BASIC语言编写的应用软件程序包。通过检查盘面,发现磁头槽0磁道附     

SALVAGE——已删除网络文件的救星

在网络操作中,系统管理员和用户经常删除文件,有些是有意的,而有些是无意的;有时候,我们会因为不小心误删除了有用的文件而懊悔不迭。不过,请不要着急,有两种办法,即UNDELETE.EXE和SALVAGE.EXE能帮助解决这一苦恼问题。 UNDELETE.EXE是DOS的一个外部命令,用它来对工作站上已删除的文件进行恢复,只要知道删除文件原处在工作站上的哪个目录下、被删文件的第一个字母是什么即可将其恢复。而SALVAGE.EXE是网络的一个菜单实用程序,用它来对网络上(例如某卷下的某个目录中)已删除的文件进行恢复,既快捷又方便。下面谈一谈如何利用SALVAGE对已删除     

Office文件误删除恢复的后遗之解决方法

Office文件误删除后恢复的方法非常多，相信大家已经掌握了不少．其中最常用的方法可能是用easyrecover恢复，easyrecover能恢复绝多大多数的文件，笔者经常使用，但是在使用过程中发现了一个问题．恢复的Office文件有很多不能打开，还是无法使用。笔者结合日常的经验使用了以下几种方法使文件可用率提高了不少．在此想和大家一起讨论一下。     

受损软盘的文件修复

本文提出了一种恢复受损软盘上文件的方法,即把坏盘上的所有扇区映象成一个文件,对该文件修改(或不经修改)后,再映象到一个好盘上,然后在好盘上把原盘的各文件读出。该方法还对EAT表交叉拷贝,可以自动修复FAT表。     

基于虚拟文件操作的文件检查点设置

实现分布/并行系统容错的基础是单进程检查点设置和卷回恢复技术,而对活动文件信息进行保存和恢复则是这种技术的重要方面.提出一种虚拟文件操作策略,实现了对用户文件的检查点设置,有效地解决了发生故障时用户文件内容与进程全局状态的不一致的问题.该方法通过文件块式管理、检查点分布操作等技术,使得在空间开销、正常运行时间、恢复时间等性能指标上优于其他方法,并且具有对用户透明、可最大限度地保留已完成工作的特点.     

实用文件分割存贮程序

在目前的微机系统中,其软磁盘容量最大的是3.5寸1.44M高密盘,而目前的很多应用软件(如汉字系统中的高点阵字库)其长度远远超出软磁盘的容量,这就给这些大文件的备份和拷贝等工作带来了诸多不便。DOS系统中能够完成这一工作的只有BACKUP备份命令和相应的RESTORE恢复命令,用此命令虽然可行,但存在一定的局限性,比如对DOS版本要求严格,不同的版本之间不能正确备份和恢复;再有就是备份出的文件不能直接使用等。所以编制一个理想的文件分割程序,对于完善DOS的功能是非常必要的。文后所附程序,是一个功能齐全方便实用的文件分割程序,可做为DOS外部命令来使用。     

具有多重签名功能的文件签名管理系统

本文介绍了一个利用公开密钥数字签名技术开发的文件签名管理系统。本系统能够对任意格式的电子文件进行不限次数的签名及其认证,在签名时还可以附上任意格式的意见文件,对于原文及意见文件可以调用原生成软件进行浏览。     

COM文件转换为.EXE文件

·COM文件是大家熟悉的DOS可执行文件。由于它存在着文件长度受限制、不允许堆栈段等缺陷,在某些应用中,比如二次开发.COM文件(扩充功能、加密处理等),经常会碰到.COM文件长度超过64K后要将其转换为.EXE文件的问题,亦即EXE2BIN命令的逆过程。然而,有关的介绍资料却很少。作者通过对.COM和.EXE文件结构的分析,用宏汇编语言编写了一个名为COM2EXE.ASM的     

Multimedia file forensics system exploiting file similarity search

With the fast increase of multimedia contents, efficient forensics investigation methods for multimedia files have been required. In multimedia files, the similarity means that the identical media (audio and video) data are existing among multimedia files. This paper proposes an efficient multimedia file forensics system based on file similarity search of video contents. The proposed system needs two key techniques. First is a media-aware information detection technique. The first critical step for the similarity search is to find the meaningful keyframes or key sequences in the shots through a multimedia file, in order to recognize altered files from the same source file. Second is a video fingerprint-based technique (VFB) for file similarity search. The byte for byte comparison is an inefficient similarity searching method for large files such as multimedia. The VFB technique is an efficient method to extract video features from the large multimedia files. It also provides an independent media-aware identification method for detecting alterations to the source video file (e.g., frame rates, resolutions, and formats, etc.). In this paper, we focus on two key challenges: to generate robust video fingerprints by finding meaningful boundaries of a multimedia file, and to measure video similarity by using fingerprint-based matching. Our evaluation shows that the proposed system is possible to apply to realistic multimedia file forensics tools.

     

Fault tolerant file models for parallel file systems: introducing distribution patterns for every file

Parallelism in file systems is obtained by using several independent server nodes supporting one or more secondary storage devices. This approach increases the performance and scalability of the system, but a fault in one single node can stop the whole system. To avoid this problem, data must be stored using some kind of redundant technique, so any data stored in a faulty element can be recovered. Fault tolerance can be provided in I/O systems by using replication or RAID based schemes. However, most of the current systems apply the same technique for all files in the system. This paper describes the fault tolerance support provided by Expand, a parallel file system based on standard servers. This support can be applied to other parallel file systems with many benefices: fault tolerance at file level, flexible definition of fault tolerance scheme to be used, possibility to change the fault tolerant support used for a file, etc.

Patents: to file or not to file?

In the previous paper, the author discussed the three criteria for patentability: novelty, usefulness, and nonobviousness and the practical value of obtaining a patent in terms of discoverability - the ease with which infringement can be determined, and in terms of avoidance - the ease with which a potential user of someone's invention could achieve similar results without using that invention. In this paper, the author continues the discussion of the practical value of a patent. Suppose that you have decided that your invention is novel, useful, and nonobvious. Further, suppose that you have decided that your invention is unavoidable (that is, it is the only reasonable way to do whatever it does), and that infringement would be easily discoverable. The remaining questions as to whether to proceed with a patent application are: Who would be likely to use your invention? Based on your answer to #1, what is the value to you of owning the patent? How much will it cost you to obtain the patent? Will your patent stand up in court if it is challenged?.     

A prediction-based dynamic file assignment strategy for parallel file systems

Nowadays, the rapid development of the internet calls for a high performance file system, and a lot of efforts have already been devoted to the issue of assigning nonpartitioned files in a parallel file system with the aim of pursuing a prompt response to requests. Yet most of the existing strategies still fail to bring about an optimal performance on system mean response time metrics, and new strategies which can achieve better performance in terms of mean response time become indispensable for parallel file systems. This paper, while addressing the issue of assigning nonpartitioned files in parallel file systems where the file accesses exhibit Poisson arrival rates and fixed service times, presents an on-line file assignment strategy, named prediction-based dynamic file assignment (PDFA), to minimize the mean response time among disks under different workload conditions, and a comparison of the PDFA with the well-known file assignment algorithms, such as HP and SOR. Comprehensive experimental results show that PDFA is able to improve the performance consistently in terms of mean response time among all algorithms for comparison.     

Data file management

This paper reviews the different types of data files and methods of storing and retrieving information using sequential access and random access files. A data management program that contains specifications on 300 robot models is used to show how to: (1) create a new data file, (2) add information to an existing file, (3) modify records within a file, (4) display information from a data file, and (5) to analyze data from individual records.     

Grid file concurrency

The grid file is a partial match search structure which is equally efficient for range queries involving any subset of the attributes of the key of a file. This paper proposes a method of safe correct concurrent access to the grid file, using a minimum number of locks. In particular, searchers are never locked out from any part of the search structure.     

MP4共享FLV数据研究与实现

MP4共享FLV数据的研究旨在以极小存储空间高效方便地实现MP4文件与FLV文件的数据共享,满足主流移动平台的在线视频播放。通过研究发现,只需要利用FLV文件1%左右的存储空间,就可以支持移动设备观看FLV视频内容。MP4共享FLV数据具有很高的理论价值和现实意义。     

一种文件转换器的设计与实现

随着计算机技术的飞速发展,数据和信息以各种文件格式被组织并存储在计算机系统中。为了提高对数据和信息的共享效率,需要进行文件格式转换,支持不同软件的处理和应用需要。采用经典的软件开发方法和技术,设计和实现一种文件格式转换器,支持将一种专用的文本格式文件转换到关系数据库文件。