Comp Sci Unit 1 (1.1.1 - 1.1.14)

What makes a new system feasible?

Technical, economic, legal, operational, schedule feasibility

Change Management

The transition of shifting the client from an old system to a new one

What makes change management difficult?

• Employee Training
• How the system will be implemented
• Cost
• Layoffs

Legacy system

old technology, hardware, computer system, or application

Business merger

Combination of 2+ businesses

Keep both systems to have the same functionality

High maintenance cost

Replace both information systems with new one

Increased initial cost

Select best information systems from each company and combine

Difficult for employees

Select just one company’s information systems

Policy problems

Local host

Larger and complex systems

Remote host

No necessary hardware
Administration to outsource responsibilities

Software as a Service (SaaS)

Services on the web

Pros of (SaaS)

Cheaper to maintain, subscription service

Cons of (SaaS)

Data loss if company goes out of business, connection may be worse, integration is difficult

Direct installation process

Unplug old system and plug new system simultaneously

Pros of direct installation process

Quick and cheap, if the system is not critical

Cons of direct installation process

Risky

Parallel installation process

Run both systems at the same time, unplug the old one when satisfied

Pros of parallel installation process

Limited risk, outputs can be compared

Cons of parallel installation process

Expensive, unhelpful if new system is different

Phased installation process

Upgrade one module of the system at a time

Pros of phased installation process

Limited risk, good for big systems

Cons of phased installation process

Training and adoption takes long, doesn’t always apply

Pilot installation process

New system in one site, extended to others over time

Pros of pilot installation process

Less risk, proof of concept

Cons of pilot installation process

Sites may be different, doesn’t always apply

Data migration

The transfer of data between different formats, storage types and computer systems

Problems of data migration

Incapability to move data due to different systems/languages

Ways of testing

Test commands, inputs, menu functions

Use of testing functions

To see if the functions work and to fix them accordingly

Importance of user documentation

Allows the code to be more organized and understandable

Pros of self instruction

Cheap, Quick, Flexible

Cons of self instruction

Less focus, less help, less learning

Pros of formal class

In depth, teacher assistance

Cons of formal class

Expensive, Long

Pros of Online classes

Individual, in-depth, anywhere

Cons of Online classes

Expensive, Errors, Time consuming

Causes of data loss

Malicious Activity, Natural Disasters

Malicious Activity examples

Internal activity by employees, destruction, viruses

Natural disaster examples

Floods, earthquakes, fires

Consequences of data loss

Loss of records, data and information

Pros of manual updates

Can be printed and kept on hand

Cons of manual updates

Harder to look up information can’t help with very specific problems

Pros of email support

Can help with specific problems

Cons of email support

Takes a while to get a response

Pros of frequently asked questions

No one required to assist

Cons of frequently asked questions

Might not have an answer to your specific question

Methods used to prevent data loss

Failover, redundancy, removable media, offsite/online storage

Failover

When a standby computer is used while the primary computer is unable to work

Redundancy

Duplicating data to another computer to prevent loss if the primary computer becomes unable to work

Removable Media

Storing data on an external device such as a USB, or disk, and can be used on multiple computers

Offsite/Online Storage

Storing data offline with an encryption key / Storing data online on sites like Google drive with an encryption key

Strategies for managing releases and updates

Manual, Automatic updates

Manual updates

User gets notified on the update
User can decide if they want to update
They must allow the update to work

Automatic update

Application constantly checks for updates
Users does not need to confirm update
User does not need to go through the process of updating