File and Console I/O
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Use of Seek When Writing Or Reading Binary Files
Title stata.com file — Read and write text and binary files Description Syntax Options Remarks and examples Stored results Reference Also see Description file is a programmer’s command and should not be confused with import delimited (see [D] import delimited), infile (see[ D] infile (free format) or[ D] infile (fixed format)), and infix (see[ D] infix (fixed format)), which are the usual ways that data are brought into Stata. file allows programmers to read and write both text and binary files, so file could be used to write a program to input data in some complicated situation, but that would be an arduous undertaking. Files are referred to by a file handle. When you open a file, you specify the file handle that you want to use; for example, in . file open myfile using example.txt, write myfile is the file handle for the file named example.txt. From that point on, you refer to the file by its handle. Thus . file write myfile "this is a test" _n would write the line “this is a test” (without the quotes) followed by a new line into the file, and . file close myfile would then close the file. You may have multiple files open at the same time, and you may access them in any order. 1 2 file — Read and write text and binary files Syntax Open file file open handle using filename , read j write j read write text j binary replace j append all Read file file read handle specs Write to file file write handle specs Change current location in file file seek handle query j tof j eof j # Set byte order of binary file file set handle byteorder hilo j lohi j 1 j 2 Close -
CSE 220: Systems Programming Input and Output
CSE 220: Systems Programming Input and Output Ethan Blanton Department of Computer Science and Engineering University at Buffalo Introduction Unix I/O Standard I/O Buffering Summary References I/O Kernel Services We have seen some text I/O using the C Standard Library. printf() fgetc() … However, all I/O is built on kernel system calls. In this lecture, we’ll look at those services vs. standard I/O. © 2020 Ethan Blanton / CSE 220: Systems Programming Introduction Unix I/O Standard I/O Buffering Summary References Everything is a File These services are particularly important on Unix systems. On Unix, “everything is a file”. Many devices and services are accessed by opening device nodes. Device nodes behave like (but are not) files. Examples: /dev/null: Always readable, contains no data. Always writable, discards anything written to it. /dev/urandom: Always readable, reads a cryptographically secure stream of random data. © 2020 Ethan Blanton / CSE 220: Systems Programming Introduction Unix I/O Standard I/O Buffering Summary References File Descriptors All access to files is through file descriptors. A file descriptor is a small integer representing an open file in a particular process. There are three “standard” file descriptors: 0: standard input 1: standard output 2: standard error …sound familiar? (stdin, stdout, stderr) © 2020 Ethan Blanton / CSE 220: Systems Programming Introduction Unix I/O Standard I/O Buffering Summary References System Call Failures Kernel I/O (and most other) system calls return -1 on failure. When this happens, the global variable errno is set to a reason. Include errno.h to define errno in your code. -
Introduction to Unix
Introduction to Unix Rob Funk <[email protected]> University Technology Services Workstation Support http://wks.uts.ohio-state.edu/ University Technology Services Course Objectives • basic background in Unix structure • knowledge of getting started • directory navigation and control • file maintenance and display commands • shells • Unix features • text processing University Technology Services Course Objectives Useful commands • working with files • system resources • printing • vi editor University Technology Services In the Introduction to UNIX document 3 • shell programming • Unix command summary tables • short Unix bibliography (also see web site) We will not, however, be covering these topics in the lecture. Numbers on slides indicate page number in book. University Technology Services History of Unix 7–8 1960s multics project (MIT, GE, AT&T) 1970s AT&T Bell Labs 1970s/80s UC Berkeley 1980s DOS imitated many Unix ideas Commercial Unix fragmentation GNU Project 1990s Linux now Unix is widespread and available from many sources, both free and commercial University Technology Services Unix Systems 7–8 SunOS/Solaris Sun Microsystems Digital Unix (Tru64) Digital/Compaq HP-UX Hewlett Packard Irix SGI UNICOS Cray NetBSD, FreeBSD UC Berkeley / the Net Linux Linus Torvalds / the Net University Technology Services Unix Philosophy • Multiuser / Multitasking • Toolbox approach • Flexibility / Freedom • Conciseness • Everything is a file • File system has places, processes have life • Designed by programmers for programmers University Technology Services -
File Handling in Python
hapter C File Handling in 2 Python There are many ways of trying to understand programs. People often rely too much on one way, which is called "debugging" and consists of running a partly- understood program to see if it does what you expected. Another way, which ML advocates, is to install some means of understanding in the very programs themselves. — Robin Milner In this Chapter » Introduction to Files » Types of Files » Opening and Closing a 2.1 INTRODUCTION TO FILES Text File We have so far created programs in Python that » Writing to a Text File accept the input, manipulate it and display the » Reading from a Text File output. But that output is available only during » Setting Offsets in a File execution of the program and input is to be entered through the keyboard. This is because the » Creating and Traversing a variables used in a program have a lifetime that Text File lasts till the time the program is under execution. » The Pickle Module What if we want to store the data that were input as well as the generated output permanently so that we can reuse it later? Usually, organisations would want to permanently store information about employees, inventory, sales, etc. to avoid repetitive tasks of entering the same data. Hence, data are stored permanently on secondary storage devices for reusability. We store Python programs written in script mode with a .py extension. Each program is stored on the secondary device as a file. Likewise, the data entered, and the output can be stored permanently into a file. -
Storage Devices, Basic File System Design
CS162 Operating Systems and Systems Programming Lecture 17 Data Storage to File Systems October 29, 2019 Prof. David Culler http://cs162.eecs.Berkeley.edu Read: A&D Ch 12, 13.1-3.2 Recall: OS Storage abstractions Key Unix I/O Design Concepts • Uniformity – everything is a file – file operations, device I/O, and interprocess communication through open, read/write, close – Allows simple composition of programs • find | grep | wc … • Open before use – Provides opportunity for access control and arbitration – Sets up the underlying machinery, i.e., data structures • Byte-oriented – Even if blocks are transferred, addressing is in bytes What’s below the surface ?? • Kernel buffered reads – Streaming and block devices looks the same, read blocks yielding processor to other task • Kernel buffered writes Application / Service – Completion of out-going transfer decoupled from the application, File descriptor number allowing it to continue - an int High Level I/O streams • Explicit close Low Level I/O handles 9/12/19 The cs162file fa19 L5system abstraction 53 Syscall registers • File File System descriptors File Descriptors – Named collection of data in a file system • a struct with all the info I/O Driver Commands and Data Transfers – POSIX File data: sequence of bytes • about the files Disks, Flash, Controllers, DMA Could be text, binary, serialized objects, … – File Metadata: information about the file • Size, Modification Time, Owner, Security info • Basis for access control • Directory – “Folder” containing files & Directories – Hierachical -
Chapter 10 Streams Streams Text Files and Binary Files
Streams Chapter 10 • A stream is an object that enables the flow of File I/O data between a ppgrogram and some I/O device or file – If the data flows into a program, then the stream is called an input stream – If the dtdata flows out of a program, then the stream is called an output stream Copyright © 2012 Pearson Addison‐Wesley. All rights reserved. 10‐2 Streams Text Files and Binary Files • Input streams can flow from the kbkeyboar d or from a • Files that are designed to be read by human beings, file and that can be read or written with an editor are – StSystem. in is an itinput stream tha t connects to the called text files keyboard – Scanner keyy(y);board = new Scanner(System.in); Text files can also be called ASCII files because the data they contain uses an ASCII encoding scheme • Output streams can flow to a screen or to a file – An advantage of text files is that the are usually the same – System.out is an output stream that connects to the screen on all computers, so tha t they can move from one System.out.println("Output stream"); computer to another Copyright © 2012 Pearson Addison‐Wesley. All rights reserved. 10‐3 Copyright © 2012 Pearson Addison‐Wesley. All rights reserved. 10‐4 Text Files and Binary Files Writing to a Text File • Files tha t are didesigne d to be read by programs and • The class PrintWriter is a stream class that consist of a sequence of binary digits are called binary files that can be used to write to a text file – Binary files are designed to be read on the same type of – An object of the class PrintWriter has the computer and with the same programming language as the computer that created the file methods print and println – An advantage of binary files is that they are more efficient – These are similar to the System.out methods to process than text files of the same names, but are used for text file – Unlike most binary files, Java binary files have the advantage of being platform independent also output, not screen output Copyright © 2012 Pearson Addison‐Wesley. -
Automatic Porting of Binary File Descriptor Library
Automatic Porting of Binary File Descriptor Library Maghsoud Abbaspour+, Jianwen Zhu++ Technical Report TR-09-01 September 2001 + Electrical and Computer Engineering University of Tehran, Iran ++ 10 King's College Road Edward S. Rogers Sr. Electrical and Computer Engineering University of Toronto, Ontario M5S 3G4, Canada [email protected] [email protected] Abstract Since software is playing an increasingly important role in system-on-chip, retargetable compi- lation has been an active research area in the last few years. However, the retargetting of equally important downstream system tools, such as assemblers, linkers and debuggers, has either been ignored, or falls short of production quality due to the complexity involved in these tools. In this paper, we present a technique that can automatically retarget the GNU BFD library, the foundation library for a suite of binary tools. Other than having all the advantages enjoyed by open-source software by aligning to a de facto standard, our technique is systematic, as a result of using a formal model of abstract binary interface (ABI) as a new element of architectural model; and simple, as a result of leveraging free software to the largest extent. Contents 1 Introduction 1 2 Related Work 2 3 Binary File Descriptor Library (BFD) 3 4 ABI Modeling 5 5 Retargetting BFD 9 6 Implementation and Experiments 10 7 Conclusion 12 8 References 12 i 1 Introduction New products in consumer electronics and telecommunications are characterized by increasing functional complexity and shorter design cycle. It is generally conceived that the complexity problem can be best solved by the use of system-on-chip (SOC) technology. -
Linux Kernel and Driver Development Training Slides
Linux Kernel and Driver Development Training Linux Kernel and Driver Development Training © Copyright 2004-2021, Bootlin. Creative Commons BY-SA 3.0 license. Latest update: October 9, 2021. Document updates and sources: https://bootlin.com/doc/training/linux-kernel Corrections, suggestions, contributions and translations are welcome! embedded Linux and kernel engineering Send them to [email protected] - Kernel, drivers and embedded Linux - Development, consulting, training and support - https://bootlin.com 1/470 Rights to copy © Copyright 2004-2021, Bootlin License: Creative Commons Attribution - Share Alike 3.0 https://creativecommons.org/licenses/by-sa/3.0/legalcode You are free: I to copy, distribute, display, and perform the work I to make derivative works I to make commercial use of the work Under the following conditions: I Attribution. You must give the original author credit. I Share Alike. If you alter, transform, or build upon this work, you may distribute the resulting work only under a license identical to this one. I For any reuse or distribution, you must make clear to others the license terms of this work. I Any of these conditions can be waived if you get permission from the copyright holder. Your fair use and other rights are in no way affected by the above. Document sources: https://github.com/bootlin/training-materials/ - Kernel, drivers and embedded Linux - Development, consulting, training and support - https://bootlin.com 2/470 Hyperlinks in the document There are many hyperlinks in the document I Regular hyperlinks: https://kernel.org/ I Kernel documentation links: dev-tools/kasan I Links to kernel source files and directories: drivers/input/ include/linux/fb.h I Links to the declarations, definitions and instances of kernel symbols (functions, types, data, structures): platform_get_irq() GFP_KERNEL struct file_operations - Kernel, drivers and embedded Linux - Development, consulting, training and support - https://bootlin.com 3/470 Company at a glance I Engineering company created in 2004, named ”Free Electrons” until Feb. -
[MS-CFB]: Compound File Binary File Format
[MS-CFB]: Compound File Binary File Format Intellectual Property Rights Notice for Open Specifications Documentation . Technical Documentation. Microsoft publishes Open Specifications documentation (“this documentation”) for protocols, file formats, data portability, computer languages, and standards support. Additionally, overview documents cover inter-protocol relationships and interactions. Copyrights. This documentation is covered by Microsoft copyrights. Regardless of any other terms that are contained in the terms of use for the Microsoft website that hosts this documentation, you can make copies of it in order to develop implementations of the technologies that are described in this documentation and can distribute portions of it in your implementations that use these technologies or in your documentation as necessary to properly document the implementation. You can also distribute in your implementation, with or without modification, any schemas, IDLs, or code samples that are included in the documentation. This permission also applies to any documents that are referenced in the Open Specifications documentation. No Trade Secrets. Microsoft does not claim any trade secret rights in this documentation. Patents. Microsoft has patents that might cover your implementations of the technologies described in the Open Specifications documentation. Neither this notice nor Microsoft's delivery of this documentation grants any licenses under those patents or any other Microsoft patents. However, a given Open Specifications document might be covered by the Microsoft Open Specifications Promise or the Microsoft Community Promise. If you would prefer a written license, or if the technologies described in this documentation are not covered by the Open Specifications Promise or Community Promise, as applicable, patent licenses are available by contacting [email protected]. -
A Platform Architecture for Sensor Data Processing and Verification in Buildings
A Platform Architecture for Sensor Data Processing and Verification in Buildings Jorge Ortiz Electrical Engineering and Computer Sciences University of California at Berkeley Technical Report No. UCB/EECS-2013-196 http://www.eecs.berkeley.edu/Pubs/TechRpts/2013/EECS-2013-196.html December 3, 2013 Copyright © 2013, by the author(s). All rights reserved. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission. A Platform Architecture for Sensor Data Processing and Verification in Buildings by Jorge Jose Ortiz A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Computer Science in the Graduate Division of the University of California, Berkeley Committee in charge: Professor David E. Culler, Chair Professor Randy H. Katz Professor Paul Wright Fall 2013 A Platform Architecture for Sensor Data Processing and Verification in Buildings Copyright 2013 by Jorge Jose Ortiz 1 Abstract A Platform Architecture for Sensor Data Processing and Verification in Buildings by Jorge Jose Ortiz Doctor of Philosophy in Computer Science University of California, Berkeley Professor David E. Culler, Chair This thesis examines the state of the art of building information systems and evaluates their architecture in the context of emerging technologies and applications for deep analysis of the built environment. -
Plan 9 from Bell Labs
Plan 9 from Bell Labs “UNIX++ Anyone?” Anant Narayanan Malaviya National Institute of Technology FOSS.IN 2007 What is it? Advanced technology transferred via mind-control from aliens in outer space Humans are not expected to understand it (Due apologies to lisperati.com) Yeah Right • More realistically, a distributed operating system • Designed by the creators of C, UNIX, AWK, UTF-8, TROFF etc. etc. • Widely acknowledged as UNIX’s true successor • Distributed under terms of the Lucent Public License, which appears on the OSI’s list of approved licenses, also considered free software by the FSF What For? “Not only is UNIX dead, it’s starting to smell really bad.” -- Rob Pike (circa 1991) • UNIX was a fantastic idea... • ...in it’s time - 1970’s • Designed primarily as a “time-sharing” system, before the PC era A closer look at Unix TODAY It Works! But that doesn’t mean we don’t develop superior alternates GNU/Linux • GNU’s not UNIX, but it is! • Linux was inspired by Minix, which was in turn inspired by UNIX • GNU/Linux (mostly) conforms to ANSI and POSIX requirements • GNU/Linux, on the desktop, is playing “catch-up” with Windows or Mac OS X, offering little in terms of technological innovation Ok, and... • Most of the “modern ideas” we use today were “bolted” on an ancient underlying system • Don’t believe me? A “modern” UNIX Terminal Where did it go wrong? • Early UNIX, “everything is a file” • Brilliant! • Only until people started adding “features” to the system... Why you shouldn’t be working with GNU/Linux • The Socket API • POSIX • X11 • The Bindings “rat-race” • 300 system calls and counting.. -
File Systems
“runall” 2002/9/24 page 305 CHAPTER 10 File Systems 10.1 BASIC FUNCTIONS OF FILE MANAGEMENT 10.2 HIERARCHICAL MODEL OF A FILE SYSTEM 10.3 THE USER’S VIEW OF FILES 10.4 FILE DIRECTORIES 10.5 BASIC FILE SYSTEM 10.6 DEVICE ORGANIZATION METHODS 10.7 PRINCIPLES OF DISTRIBUTED FILE SYSTEMS 10.8 IMPLEMENTING DISTRIBUTED FILE SYSTEM Given that main memory is volatile, i.e., does not retain information when power is turned off, and is also limited in size, any computer system must be equipped with secondary memory on which the user and the system may keep information for indefinite periods of time. By far the most popular secondary memory devices are disks for random access purposes and magnetic tapes for sequential, archival storage. Since these devices are very complex to interact with, and, in multiuser systems are shared among different users, operating systems (OS) provide extensive services for managing data on secondary memory. These data are organized into files, which are collections of data elements grouped together for the purposes of access control, retrieval, and modification. A file system is the part of the operating system that is responsible for managing files and the resources on which these reside. Without a file system, efficient computing would essentially be impossible. This chapter discusses the organization of file systems and the tasks performed by the different components. The first part is concerned with general user and implementation aspects of file management emphasizing centralized systems; the last sections consider extensions and methods for distributed systems. 10.1 BASIC FUNCTIONS OF FILE MANAGEMENT The file system, in collaboration with the I/O system, has the following three basic functions: 1.