CMPSC-235 Final Exam Study Guide

Hierarchy of classes:

-Superclasses or general classes are at the top -Subclasses or specific classes are at the bottom -Subclasses inherit attributes and methods from the superclasses above them -Classes with instances are concrete classes -Abstract classes only produce templates for more specific classes.

Usability:

A way for designers to evaluate the systems and interfaces they create with an eye toward addressing as many HCI concerns as thoroughly as possible

Information System Utility Evaluation:

A way to evaluate a new system based on utilities.

Consistency:

Achieved by displaying information in the same area on multiple screens or by grouping information logically, guideline for display screen design - keep display presentation consistent

Full system testing with test data:

Adequate documentation in procedure manuals. Are procedure manuals clear enough? Do work flows actually "flow"? Is output correct and do users understand this output?

Change management:

Aimed at helping system users to adopt the new system and use it productively.

Top-down approach, modular design:

Allows the systems analyst to ascertain overall organizational objectives and how they are best met in an overall system. The system is divided into subsystems and their requirements

Command language:

Allows the user to control the application with a series of keystrokes, commands, phrases, or some sequence of these.

Pull technology:

Allows user to take formatted data from the Web

Composite (concatenated) key:

Also known as composite primary key is a combination of two or more column values used to define a key in a table

Attributes:

An attribute describes some property that is possessed by all objects of the class.

Sink:

An external entity that receives the data.

Goal:

Answers the why of information systems by asking whether the output has value in helping the organization achieve its objectives.

Optimizing vs Satisficing :

Any system represents some kind of tradeoff between functionality (meeting the business needs) and the resources available (constraints). The goal of system design is an improved system, one that better meets the needs of the organization than the system that came before it. The perfect system does not exist.

Transaction file:

Are short records; contain information used to update master files

Data couple:

Arrow with empty circle, shows the data one module passes to another

Control couple:

Arrow with filled in circle, shows message (flag) which one module sends to another

System support:

Assistance in using the system

Output bias:

Bias introduced in three ways - how info is sorted, setting of acceptable limits, choice of graphics

Modules:

Breaking the programming into logical, manageable portions

Components of the user interface - action:

Characterizes the human-to-computer portion.

Link testing with test data/ string testing:

Checks to see if programs that are interdependent can actually work together within a system as planned

Gradual (phased) conversion:

Combines best features of parallel and direct conversion. Volume of transaction is gradually increased. Advantage is that users get involved with the system gradually.

Full system testing with live data:

Compare the new system output with the existing system output. Comparison of new system's output with what you know to be correctly processed output from the old system

Report design - constant information:

Constant information does not change when the report is printed

Table file:

Contain data used to calculate more data or performance measures

Master file:

Contain records for a group of entities. Contain all pertinent information about a data entity; large records

Context level diagram (single process bubble represents whole system):

Contains only one process, representing the entire system. Process bubble is given the number 0. All external entities, as well as major data flows are shown.Uses arrows, squares, and rectangle with rounded corners.

Storyboard:

Could be used to show the differences between screens, can show visitor how to navigate throughout the website

Buffer overflow:

Created when a programmer allocates a certain amount of memory to hold a piece of information.

Dashboard:

Data has context, display proper amount of summarization and precision, choose appropriate performance measures for display, present data fairly, limit variety of item types, highlight important data

Key:

Data items in a record used to identify the record

Conversion strategies:

Direct changeover, parallel conversion, gradual or phased conversion, modular prototype conversion, and distributed conversion.

Feedback to the user is only necessary when there is an error condition.

False

Open input:

Free-form text entry (ex: text boxes, text area)

Simple sequence:

Identifies person/place/thing, assigns number to something that needs to be numbered

Bottom-up design:

Identifying the processes that need computerization as they arise

Three-clicks rule:

Include a navigation bar and links to homepage on every website page

Metaphors for user interface - document:

Input/output screens structured as paper documents (ex: customer order)

Data Dictionary:

It collects and coordinates data terms, and confirms what each term means to different people in the organization.

Screen design:

Keep is simple and consistent, Facilitate user movement and create an attractive screen

Minimal user action:

Keying codes instead of whole words. Entering data that are not already stored on files. Supplying the editing characters. Using default values for fields on entry screens.

Transparency (Don Norman):

Makes it easy to determine what actions are possible at any moment. Makes things visible, including the conceptual model of the system, the alternative actions, and the results of actions. Make it easy to evaluate the current state of the system.

User interface design objectives:

Match the user interface to the task, Make the user interface efficient, Provide appropriate feedback to users, Generate usable queries. Improve productivity of computer users.

Secondary (alternate) key:

May or may not be unique. Multiple of these keys are allowed

Horizontal balancing:

Means that all output data flow must be either on input data flow or described in the process logic. It is used to verify that each process has the required data dictionary entries defined and the formulas and logic necessary to produce the output

Process Analysis:

Methods available for documenting and analyzing the logic of structured decisions include structured English, decision tables, and decision trees.

Primary key:

Must be unique

Insert anomaly:

Occurs when the entire primary key is not known and the database cannot insert a new record, which would violate entity integrity.

Direct changeover (a.k.a. crash conversion, cold turkey):

Old system stops, new one starts, Needs extensive testing. Risky approach to conversion. Users may resent being forced into using an unfamiliar system without recourse.

Base element:

One that has been initially keyed into the system.

Derived element:

One that is created by a process, usually as the result of a calculation or a series of decision-making statements

Interface (boundary):

Provide means for users to work with the system. Human interfaces may be a display, window, Web form, dialogue box, touch-tone telephone, or other way for users to interact with the system. System interfaces involve sending data to or receiving data from others.

Post-implementation activities:

Provide support, provide maintenance, and assess the project

External entity:

Represent another department, a business, a person, or a machine. Entities represented on an entity-relationship diagram. (Noun)

Closed input:

Restricted input, finite number of possible responses (ex: check boxes, option/radio buttons, list/drop-down list boxes, sliders, spin buttons, image maps)

Parallel conversion:

Run the old and new systems at the same time. The advantage is that you can check new data against old data.

Voice recognition:

Speak in natural language (ex: Siri)

Ben Shneiderman's Golden Rules of Interface Design:

Strive for Consistency, Shortcuts for Frequent Users, Offer Informative Feedback, Design Dialogs to yield closure, Offer error prevention and simple error handling, Permit easy reversal of actions, Support Internal Locus of Control, Reduce Short-Term Memory Load

Gestures:

Tapping, swiping, and pinching gestures can be used with touch-sensitive smartphones/tablets

Work file:

Temporary files; connect one part of the process with another part of the process that runs at a different time batch mode processing file <- records <- fields table (relation) row (record, tuple) column (attribute, field)

Which is not a way to validate input?

Test for accurate character data

Sponsor:

The business person who initiated the request for the new system

Components of the user interface - presentation:

The computer-to-human- part of the transaction

Motivating adoption:

The information strategy aims to convince adopters that change is better. The political strategy uses organizational power to motivate change.

Adopters:

The people who must change

Structure charts:

The recommended tool for designing a modular, top-down system

From the end user's point of view, the user interface is the system.

True

Desk check:

Used for program testing with test data, test valid/invalid data, errors and modified programs

Check digits:

Used to validate numeric field by performing a calculation on a part of the number and comparing result with digit stored within number - helps detect single digit miskey, transposition errors

Internal output:

Used within corporation (ex: summary report, detailed report, historical report, exception report - consists of material available on intranet)

Report design - variable information:

Variable information changes each time the report is printed

Migration planning:

What activities will be performed when and by whom

Update anomaly:

When a change to one attribute value causes the database to either contain inconsistent data or causes multiple records to need changing.

Visibility:

all user interface (controls) should be visible in terms of availability and their response to user input

Objects:

an object, represents a real-world thing or event. Objects may be customers, items, orders and so on. Objects may be GUI displays or text areas on a display. Objects are represented by and grouped into classes.

Affordance:

appearance of any control should suggest its functionality

Transformational modules:

changing input into output

Types of user interfaces:

command-language, menus, graphical user (GUI), Question-and-answer, form-fill, natural-language

Question-and-answer interface (e.g. software installation wizard):

computer displays question for user on screen, user enters answer via keyboard, computer acts on input information in programmed manner - new user may find interface most comfortable

Tab control dialog boxes:

creates a separate tab for each unique feature, places the most commonly used tabs in front and displays them first (OK, cancel, help)

Generalization:

describes a relationship between a general kind of thing and a more specific kind of thing. Described as an "is a" relationship. Used for a modeling class inheritance and specialization. General class is a parent, base, or superclass. Specialized class is a child, derived, or subclass

Control modules:

determining the overall program logic

Codes and coding of data:

easier to retrieve than searching for many variations in free-form text entry, coding helps efficiency: helps reduce number of items enters, requires less time to enter coded data, help in sorting data, can save memory/storage

Block sequence codes:

extension of sequence code

Database:

formally defined and centrally controlled store of data intended for use in many different applications

Program help:

function keys, GUI pull down menu, context-sensitive help, iconic help, wizards (q/a), telephone help, online software boards/forums

Metaphors for user interface - alphanumeric commands:

interaction via fixed command words

Guidelines for coding:

keep codes concise, stable, unique, sortable, not-confusing, uniform, allow for modification, meaningful

Data entry (data capture) methods:

keyboards, QR codes, bar codes, microsoft tags, RFID, NFC, optical character recognition, magnetic ink character recognition, mark-sense forms

Standard operation and consistency:

locating titles, data, time, and operator and feedback messages in the same places on all displays. Exiting each program by the same key or menu option.

Miller's Rule (limitation of short-term memory):

magic number 7, plus or minus 2 - adults can store between 5-9 items in short-term memory

Form design:

make forms easy to fill in, ensure forms meet purpose for which they are designed, design form to assure accurate completion, keep forms attractive

mnemonic code:

memory aid, uses combo of letters/symbols = clear way to code so easily seen and understood

Metaphors for user interface - desktop:

menus as icons (click or tap images) that resemble desk objects

Types of interfaces:

natural language, question-and-answer, menus, form-fill, command-language, graphical user

Form-fill interface (e.g. for data entry):

on-screen forms displaying fields containing data items or parameters that need to be communicated to user, may be implemented using web - used for data entry

Subordinate module:

one found lower on the structure chart, called by another higher module:

Stamp coupling:

passing more data than necessary

Command button:

perform an action when a user selects it

Functional modules:

performing detailed work

Natural language:

permit users to interact with computer in everyday or natural language, no special skills required of user

Exception report:

print a line for all records that match a certain condition, a report that shows a variance from pre-defined norms; prints a line for records that match a certain set of conditions

Detail report:

print a report line for every record on the master file

Summary report:

print one line for a group of records that are used to make decisions

Graphical user interface (GUI):

provide a strong metaphor of the application, allow direct manipulation of graphical representation on screen - requires more system sophistication than other interfaces

Satisficing:

seeking a better/improved system

Optimizing:

seeking to build the perfect system

Types of codes:

single sequence, alphabetic derivation, classification, block sequence, cipher, significant digit subsets, mnemonic

Why would a company issuing credit cards use a code that is much larger than the minimum length?

so that a person would not be able to guess a credit card number and illegally use it to purchase goods

Cipher:

substitution of one letter for another, etc.

Object-oriented design:

techniques work well in situations where complicated systems are undergoing continuous maintenance, adaptation, and design. The Unified Modeling Language is an industry standard for modeling object-oriented systems. The Object-oriented approach is implemented in a number of programming languages: C++, Java, Smalltalk, etc.

GUI controls:

text boxes, text areas, checkboxes, radio buttons, option buttons, drop-down lists, sliders, spin buttons, image maps, message box

Source:

the external entity that sends the data

Composition:

the whole has a responsibility for the parts, and is a stronger relationship. If the whole is deleted, all parts are deleted.

Which of these is not an HCI guideline for dialog design?

top-down hierarchical decomposition

Design for smartphones and tablets:

touch-sensitive screens allows for finger to activate display, multi-touch gestures aka capacitive sensing, used for moving from one state to another on same screen

Alphabetic derivation code:

used approach in identifying account number

Control:

used to control the flow of activities. Many small control classes can be used to achieve classes that are reusable.

Classification:

used to distinguish one group of data with special characteristics, consists of single letter/number, listed in manuals or posted so can be easily located

FOLKLORE method:

Gathers information that is often shared among users but is seldom written down.

Referential integrity:

Governs the nature of records in a one-to-many relationship. All foreign keys in one table must have a matching record in the parent table.

Data Flow Diagrams:

Graphically characterized data processes and flows in a business system. Structured analysis and design tools that allow the analyst to comprehend the system and subsystems visually as a set of interrelated data flows.

Deletion anomaly:

Happens when a record is deleted that results in the loss of other related data

Fly-out menu

Horizontal version of the dropdown, where submenus fly-out from side when you click over main item

Metaphors for user interface - conversation:

Interaction resembles conversation between people (ex: sequencing question and answers in expert system, natural voice interaction)

Actualization:

Involves how the information is introduced and used by the decision maker.

Loop:

Iteration

"Exploding" diagrams to create child diagrams:

Keeping inputs and outputs within the first diagram constant, but "exploding" the rest of the original data, into 3-9 processes showing data stores and new lower-level data flows. Each process is numbered starting from the upper left-hand corner of the diagram working toward the lower right-hand corner.

Human-computer interaction (HCI):

Knowledge about the interplay among users, tasks, tasks contexts, IT, and the environments in which the systems are used comprises the basis of this.

Jakob Nielsen - Usability Attributes:

Learnability, Efficiency, Memorability, Few and Non Catastrophic Errors, and Satisfaction.

System flaws:

Major anticipated flaws, major unanticipated flaws, minor anticipated flaws, minor unanticipated flaws

Menu interface:

Provides the user with an onscreen list of available selections

On-demand report:

"printed ad-hoc report"

Periodic report:

"printed scheduled reports" , printed output that is produced on a set frequency or schedule

Coping with change:

(example: The ladies in the research department find their jobs on the line when they are introduced to a new time saying contraption--the computer.)

Form sections:

7 sections of a form - heading, identification and access, instructions, body, signature and verification, totals, comments

Record:

A collection of data items that have something in common with the entity described.

Data store:

A depository for data that allows examination, addition, and retrieval of data. Named with a noun, describing the data. Data stores can be a given a unique reference number, such as D1, D2, D3. represents a: database, database table, computerized file, filing cabinet. Cannot be connected to a sink or source

Foreign key:

A foreign key is a key used to link two tables together. A foreign key is a field (or collection of fields) in one table that refers to the PRIMARY KEY in another table.

Structural records:

A group of of fields used so that analyst does not need to repeat every time they are part of a larger structure Example: Customer = Name + Address + City + State Zip-code + Telephone Number

Methods/operations:

A method is an action that can be requested from an object of the class.

Black hole:

A process that ha only inputs, no output.

Miracle:

A process that only has only outputs, no input.

Metadata:

A reference work of data about data, information that describes data in file or database, the information that describes data in the file or database.

Data element (field, database column):

A simple piece of data that can be base or derived; should be defined in the data dictionary.

Data structure (record, database row):

A structure composed of data elements, typically described using algebraic notation to produce a view of the elements. An analyst begins with the logical design and then designs the physical data structures.

Data warehousing:

A subject-oriented, integrated, time-variant and non-volatile collection of data in support of management's decision making process.A data warehouse is a copy of transaction data specifically structured for query and analysis.

Structured English:

A technique for analyzing structured decisions based on structure logic and simple English statements, such as add, multiple, and move.

Decision Tree:

A tool for examining, describing, and documenting structured decisions. Four quadrants are drawn to describe the conditions, identify possible decision alternatives, indicate which actions should be performed, and describe the actions.

Project assessment:

Analyze what was done well, discover what activities need improvement in the future.

Form:

Answers the question of what kind of output is distributed to the decision maker.

Time:

Answers the question of when information is delivered

Place:

Answers the question of where information is distributed.

Possession:

Answers the question of who should receive output.

Instantiate

Create an object from a class (an instance)

Process specifications/minispecs:

Created for primitive processes as well as for some higher level processes on a data flow diagram

Data store (file, database table):

Data that are at rest in a system; depicted using an open-ended rectangle in data flow diagrams.

Data flow:

Data that move in a system from one place to another; input and output are depicted using an arrow with an arrowhead in data flow diagrams.

Domain integrity:

Defines rules that ensure that only valid data are stored on database record. Two forms = check constraints and rules.

Classes:

Defines the set of shared attributes and behaviors found in each object in the class. Should have a name that differentiates it from all other classes. Usually nouns, or short phrases - begin with uppercase letter

Files:

Designed and built quite rapidly and the concerns for data availability and security are minimized.

Program testing with test data:

Desk check programs, test with valid and invalid data, and check for errors and modify programs

Turnaround document:

Document that is sent out and returned

Modular prototype conversion:

Each module is tested and put into use. The advantage is that each module is thoroughly testing before being used.

Database:

Ensuring that data can be shared among users for a variety of applications.

Algebraic notation to document data structure:

Equal sign means "is composed of"; plus sign means "and"; Braces {} mean repetitive elements; Brackets [] mean for either/or situation; Parentheses () for an optional element

Resistance to change:

Even changes that benefit an organization do not necessarily benefit each individual. Adapting to new work processes requires effort, for which there may be no additional compensation.

Training:

Every new system requires new skills. New skills may involve use of the technology itself. New skills may be needed to handle the changed business processes.

Second normal form (2NF):

Remove any partial dependencies. A relation is created for the data that are only dependent on part of the key and another for data that are dependent on both parts.

First normal form (1NF):

Remove any repeating groups. All repeating groups are moved into a new table.

Third normal form (3NF):

Remove any transitive dependencies. A single data item may be present on many records.

Ongoing system maintenance:

Repair or fix discovered bugs or errors. Add minor enhancements/improvements to provide added value.

Attribute:

Represent some characteristics of an entity

System documentation:

Requirement for total quality assurance, serves as guidelines for users, communication tool, maintenance/development reference - FAQ, Help desk/technical support (email, interactive chat, fax back) timely updates to doc errors The English-language component of documentation. The key sections include: Introduction, How to use the software, What to do if things go wrong, A technical reference section, An index, and Information on how to contact the manufacturer

On the structure chart shown above, the diamond symbol underneath module 1.0 indicates what?

Selection

Report file:

Sending program output to a file rather than directly to a printer device.

Push technology:

Sends solicited or unsolicited information to a customer or client

Loosely coupled modules:

Separate modules should be relatively independent and facilitates both development and maintenance

Islands of technology:

Separate, isolated systems; unable to share data, unable to work together, duplication of effort and data entry

Mockups:

Show what output/input will look like, software available to help designer develop mockup, templates available for various types of display

Process bubble:

Shown in data flow diagrams (specifically context-level diagram) to show action(s) that are taking place; Process bubble can be drawn as a rectangle with rounded edges, or a circle, both are marked with the 0 on top.

Data flow arrow:

Shows movement of data from one point to another. Described with a noun. Arrow-head indicates the flow direction. Represents data about a person, place, or things.

Jacob Nielsen - Usability Heuristics:

Simple and Natural Dialog, Speck the User's language, Minimize User Memory Load, Consistency, Feedback, Clearly Marked Exits, Shortcuts, Good Error Messages, Prevent Errors, Help and Documentation

Simplicity:

Simple and straightforward, not cluttered - function should only be included if task analysis shows it is needed, guideline for display screen design - keep display simple

Element length:

Some elements have standard lengths, state abbreviations, zip codes, or telephone numbers.

Spaghetti code vs. structured design:

Spaghetti code is computer code with a complex and tangled control structure. Structured design is organized.

Polymorphism / method overriding:

The capability of an object-oriented program to have several versions of the same method with the same name within a superclass/subclass relationship. When a specialized class (the subclass) changes/overrides a method inherited from the general (superclass)

Dialog:

The communication between a person and the computer

User interface:

The component that helps users communicate with the computer system and/or the application system

Diagram zero: first level of decomposition (bubbles numbered with whole numbers 1, 2, 3, etc.):

The explosion of the context diagram. May include up to nine processes. Each process is numbered. Major data stores and all external entities are included. Start with the data flow from an entity on the input side. Work backward from an output data flow. Examine the data flow to or from a data store. Analyze a well-defined process.

Testing:

The new or modified application programs, procedural manuals, new hardware, and all system interfaces must be tested thoroughly.

Change agent:

The person(s) who lead the change effort

Entity integrity:

The primary key cannot have a null value. If the primary key is a composite key, none of the fields in the key can contain a null value.

Implementation:

The process of assuring that the information system is operational.

Hierarchical decomposition:

The process of decomposing a system in a top down fashion. First the system is divided into subsystems, then into functions, and then modules.

Data mining:

The process of finding anomalies, patterns and correlations within large data sets to predict outcomes. Using a broad range of techniques, you can use this information to increase revenues, cut costs, improve customer relationships, reduce risks and more.

Test data:

The purpose of the testing is confirming that the system satisfies requirements.

Associations:

The simplest type of relationship. Shown by a line on a class diagram. An object in a class may have a relationship to other objects in the same class, called a reflexive association.

Meaningful communication:

The system should present information clearly to the user. Users with less skill with a computer require more communication.

Conversion:

The technical process of replacing the old system with the new one. Designers select the method, timing, and location of the conversion process.

Normalization:

The transformation of complex user views and data to a set of smaller, stable, and easily maintainable data structures

Anomalies:

They include data redundancy, insert anomaly, and deletion anomaly.

Data truncation:

This is where the element is too small.

Conversion of old data for new system (total, gradual):

Total file conversion can be used with any system implementation method. Gradual file conversion is parallel or phase-in conversion. Records are converted only when they show some transaction activity. Size-able portion of old master-file may comprise of inactive records-less space used in new system.

External output:

Used outside organization, differs from internal output in design, distribution, and appearance (Ex: utility bills, checks, ads)

Messages (sent to objects to trigger methods):

Used to send information by an object in one class to an object in another class. Acts as a command, telling the receiving class to do something. Consists of the name of the method in the receiving class, as well as the attributes that are passed with the method name.

Inheritance:

When a new class is created from another class. The original class is the parent or base class. The new class is the child or derived class. The child class receives the attributes and methods of the parent class. When a derived class inherits all the attributes and behaviors of the base class. Reduces programming labor by using common objects easily. A required feature of object-oriented systems

Transitive dependency:

When a relation contains data that are not part of the entity.

Whole/Part:

When one class represents the whole object, and other classes represent parts

Nested menus:

When one menu can be reached by choosing it from a previous menu

Cloud computing:

When organization and individual users can use web services, database services, and application services over the internet without having to invest in corporate or personal hardware, software, or software tools

Partial dependency:

When the data are only dependent on (identified by) a part of the key.

Data redundancy:

When the same data is stored in more than one place in the database.

Distributed conversion:

When there are many installations of the same system, such as at branch offices. Install software at one office. Advantage is that problems can be detected and contained.

Aggregation:

a "has a" relationship. Provides a means of showing that the whole object is composed of the sum of its parts

7 types of feedback:

acknowledging acceptance of input, recognizing input is in correct form, notifying that input is not in the correct form, explaining a delay in processing, acknowledging that a request is completed, notifying that a request was not completed, and offering the user more detailed feedback

Improper subordination:

allowing a lower-level module to perform any function of the calling higher-level module

Abstract classes:

are general classes. No direct objects or class instances, and is only used in conjunction with specialized classes. Cannot be direct instantiated. Usually have attributes and may have a few methods.

The risk of irreversible actions:

asking for confirmation doesn't work, make actions easily reversible - less is more, fewer is better, simple, consistent

Procedure manuals:

common english-language documentation, contain background comments, process of transactions, instructions, online help, read me files - complaints that poorly organized, specific case questions not found, manual not written in plain english

Collection:

consists of a whole and its members. Members may change, but the whole retains its identity. A weak association.

Highly cohesive modules:

contains all of the tasks and only the tasks that contribute to the output of a single information function.

Flag:

control couple with multiple possible values

Validation (transactions, data)

detect errors during input - validating input transactions (submitting wrong data, submitted by unauthorized person, ask system to perform unacceptable function), validating input data (missing data, incorrect field length, data have unacceptable composition, data out of range, invalid data, data not matching with stored data, cross-reference checks) **Check missing data, check syntax, check semantics

SQL:

ex: Select NAME, PHONENUM FROM PEOPLE, DEMOGRAPHICS WHERE MAJOR='CMPSC' AND YEAR='4'....)

Captions:

line caption, boxed caption, check off caption, horizontal check off caption, table caption, combination; three screen sections (heading, body, comments and instructions)

Error messages:

specific, precise, constructive, positive tone, user-centered phrasing (free of jargon), multiple levels of messages, consistent grammatical form/terminology/abbreviations, consistent visual form

Feedback for users:

systems require feedback to monitor and change behavior, feedback compares behavior with predetermined goals and gives back info describing gap between actual and intended performance

Significant digit subset:

used to describe product via its membership in many subgroups, ability to locate items that belong to certain class, can do inquiries on portions of the code