CSCI 365 – Introduction to Large Scale Computing

Introductions Name Year Major Why you are taking this course? Acceptable answers: – I am interested in the subject... – I needed to fill an upper-level elective... – My advisor told me to take the course...

What is Large Scale Computing?

Large Scale Computing Developing really big applications Focused on highly available, transaction processing systems Applications support or solve complex problems Technologies: – Mainframes (IBM System Z, HP NonStop) – Distributed / cloud

Capabilities of a Large Scale System Large scale transaction processing – Thousands of transactions per second Support thousands of users and programs Simultaneously access and manage shared resources Database storage in Terabytes Large bandwidth communications

About Me Widener Computer Science graduate Helped setup the initial large scale course at Widener in participation with the IBM academic initiative 6+ years experience in large scale application development at JPMorgan Chase Currently in the Mortgage Banking line of business

Credit Card Processing System What does a credit card processing system do? – Authorizations: what happens when you swipe – Statements: transaction history, rewards – Customer & account system of record – Interact with network (Visa, MasterCard, acquirers) Stats: – 150MM accounts – 20MM transactions per day (peak 600TPS) – Response time under 200ms

COURSE OVERVIEW

Course Objectives Understand key concepts required for large scale application development – regardless of technology Describe programs from an application architecture perspective Gain real world insight into the use of computer science concepts

Course Objectives cont Understand the difference in creating applications which run on a PC, web-based applications, and large scale applications Become fluent in TLAs / buzzwords

Course Topics 1.System architecture overview 2.Introduction to COBOL and JCL 3.Data organization and access methods 4.Application architecture (SDLC) 5.Databases: relational vs. hierarchical 6.Transaction processing 7.High availability 8.Security

Course Format Lectures – Review key concepts – Applied and conceptual topics Labs – Hands on mainframe experience (see next slide) – Application development assignments Online – Utilize and contribute to our course wiki – largescalecomputing.wikispaces.com

Hands on Lab Experience Lab exercises will be completed on an IBM z9 mainframe at Marist College – Made available through the IBM academic initiative We use a terminal emulator to connect to the system from either the classroom or your personal computer

Course Wiki Wiki contents – Course info (lecture slides, labs, schedule, etc) – General large scale computing information Students are expected to utilize the wiki and become active contributors

Course Grading 5% lab 1 20% lab 2 20% lab 3 20% exams (2) 5% lab presentation 20% final exam 10% participation

DATA SETS & TSO Lecture 1

Quick Background IBM mainframe operating system is referred to as Z/OS

What is a Data Set? Z/OS files are called data sets – A data set is a collection of logically related data records stored on disk – Before data can be written to a data set, it must be allocated – A data set can contain: Source program Macros Data records used by a program

Types of Data Sets There are two basic types of data sets: – Sequential data set Data stored in a single piece of allocated disk space – Partitioned data set (PDS) Data can be sub-divided into multiple individual chunks or files (members) SequentialPartitioned Members

Data Set Naming Conventions Sample data set name: KC02124.LAB1.COBOL High Level Qualifier: username or catalog User Determined Qualifier: what this data relates to Type: what type of data is contained (similar to a file extension) High Level QualifierType User Determined Qualifier

Data Set Naming Conventions cont Maximum of 22 name segments (qualifiers) – Level qualifiers separated by. Each level qualifier: – 1 to 8 characters – First character must be alphabetical (A-Z) or special – Remaining: alphabetical, numeric (0-9), or hyphen – Upper case only (not case sensitive) Example: KC02124.CSCI365.LAB1.COBOL

PDS Naming Conventions Same rules as sequential data sets Need to specify a member name within the data set: KC02124.LAB1.COBOL(HELLO) KC02124.LAB1.COBOL(FUBAR)

Sequential vs. Partitioned Typically, we will use the different data set types as follows: – Sequential: raw data files – PDS: COBOL source / executables, JCL, etc

Physical Data Storage on Z/OS Data is stored on a Direct Access Storage Device (DASD) – Disk – Magnetic tape – Optical media When you hear DASD you should think disk Used for storing the OS, data sets, databases, etc

EBCDIC IBM systems since the S/360 use the Extended Binary Coded Decimal Interchange character set Developed before ASCII and is also an 8 bit character set Z/OS also supports ASCII and UNICODE for web / Java use

Catalogs A catalog associates a data set with the volume on which it is located Locating a data set on a catalog requires: – Data set name – Volume name – Unit (volume device type)

Z/OS UNIX File System Z/OS UNIX System Services (USS) allows Z/OS to access UNIX files Follows UNIX standard directory / file structure We will not be using USS in this course

How do we Interact with Z/OS? TSO – Allows users to log on to Z/OS and use a limited set of basic commands – This is called using TSO in native mode – Think command line interface ISPF – Menu structure which sits on top of TSO and provides a simpler interface for accessing commonly used TSO functions

TSO Overview TSO stands for Time Sharing Option Allows users to create an interactive session with Z/OS Basic command prompt

Lab Pre-Tasks Create a login and request to be a member of our wiki: – largescalecomputing.wikispaces.com Receive your TSO userid – Do not forget your ID!

Lab 1 Lab 1 is taken from IBMs Master the Mainframe contest Follow the instructions on the wiki: – Hints: – Return does not equal CNTL – Do not forget your password!