Which of the following is an example of IaaS?
- Cloud email accounts
- Software code libraries
- SLAs
- Cloud storage
Which of the following is an example of IaaS?
Wednesday, August 28, 2019
Many cloud customers sharing the same computing services while having isolated computing environments is an example of which of the following?
Many cloud customers sharing the same computing services while having isolated computing environments is an example of which of the following?
- XaaS
- Elasticity
- Virtualization
- Multitenancy
EXPLANATION
The term "software multitenancy" refers to a software architecture in which a single instance of software runs on a server and serves multiple tenants. A tenant is a group of users who share a common access with specific privileges to the software instance.
What is the difference between ad hoc queries and stored procedures?
What is the difference between ad hoc queries and stored procedures?
- There is no difference
- Ad hoc queries are written on the fly
- Stored procedures are embedded on the fly
- Stored procedures are written by Microsoft
EXPLANATION
Stored Procedures
- Pro: Good for short, simple queries (aka OLTP--i.e. add, update, delete, view records)
- Pro: Keeps database logic separate from business logic
- Pro: Easy to troubleshoot
- Pro: Easy to maintain
- Pro: Less bits transferred over network (i.e. only the proc name and params)
- Pro: Compiled in database
- Pro: Better security (users don't need direct table access)
- Pro: Excellent query plan caching (good for OLTP queries--benefits from plan reuse)
- Con: Excellent query plan caching (bad for OLAP queries--benefits from unique plans)
- Con: Makes you tied to that SQL vendor
Ad Hoc SQL (i.e. created in your business code)
- Pro: Good for long, complex quieres (aka OLAP--i.e. reporting or analysis)
- Pro: Flexible data access
- Pro: ORM usage is possible; can be compiled/tested in code (i.e. Linq-to-Sql or SqlAlchemy)
- Pro: Poor query plan caching (good for OLAP queries--benefits from unique plans)
- Con: Poor query plan caching (bad for OLTP queries--benefits from plan reuse)
- Con: More bits transferred over network (i.e. the whole query and params)
- Con: More difficult to maintain, if you don't use an ORM
- Con: More difficult to troubleshoot, if you don't use an ORM
- Con: More vulnerable to SQL injection attacks
They mentioned that ad-hoc queries are written "on the fly". Does this
mean that for a query to be ad-hoc it has to be written at the moment,
like in a CLI or a DBMS? What about a query that I just wrote in a
script for a specific purpose, is it still considered to be ad-hoc even
though it is part of a script?
A "production" system has a lot of "canned queries". Such queries
rarely change -- usually only when you "release" a new "version" of the
"product".An "Ad Hoc query" is a SELECT that you make up to look for something for which the canned queries don't help. It often comes from management asking something like "How many foobars happened last week?"
You will run that query once (or until you get the desired output), then toss it. Or you might develop it into a "canned query" for the "production" system, at which point it should no longer be called "ad hoc"
SNMP typically uses which UDP port number for general SNMP messages?
SNMP typically uses which UDP port number for general SNMP messages?
- 22
- 161
- 21
- 144
EXPLANATION
Simple Network Management Protocol (SNMP) is an Internet Standard protocol for collecting and organizing information about managed devices on IP networks and for modifying that information to change device behavior. Devices that typically support SNMP include cable modems, routers, switches, servers, workstations, printers, and more.[1]| Communication protocol | |
| OSI layer | Application |
|---|---|
| Port(s) | 161, 162 (Trap) |
| RFC(s) | 3411–3418 |
SNMP is widely used in network management for network monitoring. SNMP exposes management data in the form of variables on the managed systems organized in a management information base (MIB) which describe the system status and configuration. These variables can then be remotely queried (and, in some circumstances, manipulated) by managing applications.
Three significant versions of SNMP have been developed and deployed. SNMPv1 is the original version of the protocol. More recent versions, SNMPv2c and SNMPv3, feature improvements in performance, flexibility and security.
SNMP is a component of the Internet Protocol Suite as defined by the Internet Engineering Task Force (IETF). It consists of a set of standards for network management, including an application layer protocol, a database schema, and a set of data objects.[2]
In which year did Hewlett-Packard develop their first product?
In which year did Hewlett-Packard develop their first product?
- 1958
- 1988
- 1978
- 1938
EXPLANATION
HP invents first product
Drawing on Bill’s study of negative feedback, Bill and
Dave produce HP's first product, the resistance-capacitance audio oscillator, used
to test sound equipment. They name it the HP Model 200A.
1938 HP invents first product
