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Friday, August 30, 2019

HTML started out as a project named:

HTML started out as a project named:

  • SGMLuid
  • AQUIRE
  • ENQUIRE
  • ATD 

EXPLANATION

In 1980, physicist Tim Berners-Lee, a contractor at CERN, proposed and prototyped ENQUIRE, a system for CERN researchers to use and share documents. In 1989, Berners-Lee wrote a memo proposing an Internet-based hypertext system.[3] Berners-Lee specified HTML and wrote the browser and server software in late 1990. That year, Berners-Lee and CERN data systems engineer Robert Cailliau collaborated on a joint request for funding, but the project was not formally adopted by CERN. In his personal notes[4] from 1990 he listed[5] "some of the many areas in which hypertext is used" and put an encyclopedia first.
The first publicly available description of HTML was a document called "HTML Tags", first mentioned on the Internet by Tim Berners-Lee in late 1991.[6][7] It describes 18 elements comprising the initial, relatively simple design of HTML. Except for the hyperlink tag, these were strongly influenced by SGMLguid, an in-house Standard Generalized Markup Language (SGML)-based documentation format at CERN. Eleven of these elements still exist in HTML 4.[8]
HTML is a markup language that web browsers use to interpret and compose text, images, and other material into visual or audible web pages. Default characteristics for every item of HTML markup are defined in the browser, and these characteristics can be altered or enhanced by the web page designer's additional use of CSS. Many of the text elements are found in the 1988 ISO technical report TR 9537 Techniques for using SGML, which in turn covers the features of early text formatting languages such as that used by the RUNOFF command developed in the early 1960s for the CTSS (Compatible Time-Sharing System) operating system: these formatting commands were derived from the commands used by typesetters to manually format documents. However, the SGML concept of generalized markup is based on elements (nested annotated ranges with attributes) rather than merely print effects, with also the separation of structure and markup; HTML has been progressively moved in this direction with CSS.
Berners-Lee considered HTML to be an application of SGML. It was formally defined as such by the Internet Engineering Task Force (IETF) with the mid-1993 publication of the first proposal for an HTML specification, the "Hypertext Markup Language (HTML)" Internet Draft by Berners-Lee and Dan Connolly, which included an SGML Document type definition to define the grammar.[9][10] The draft expired after six months, but was notable for its acknowledgment of the NCSA Mosaic browser's custom tag for embedding in-line images, reflecting the IETF's philosophy of basing standards on successful prototypes. Similarly, Dave Raggett's competing Internet-Draft, "HTML+ (Hypertext Markup Format)", from late 1993, suggested standardizing already-implemented features like tables and fill-out forms.[11]
After the HTML and HTML+ drafts expired in early 1994, the IETF created an HTML Working Group, which in 1995 completed "HTML 2.0", the first HTML specification intended to be treated as a standard against which future implementations should be based.[12]
Further development under the auspices of the IETF was stalled by competing interests. Since 1996, the HTML specifications have been maintained, with input from commercial software vendors, by the World Wide Web Consortium (W3C).[13] However, in 2000, HTML also became an international standard (ISO/IEC 15445:2000). HTML 4.01 was published in late 1999, with further errata published through 2001. In 2004, development began on HTML5 in the Web Hypertext Application Technology Working Group (WHATWG), which became a joint deliverable with the W3C in 2008, and completed and standardized on 28 October 2014.[14]

 

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In 1995 Microsoft developed and released a cartoon looking version of Windows OS. What was it called?

In 1995 Microsoft developed and released a cartoon looking version of Windows OS. What was it called?

  • Microsoft 95b
  • Microsoft Bill
  • Microsoft Jane
  • Microsoft Bob 

EXPLANATION

Windows version Codenames Release date Release version Editions Latest build Support status
Windows 10 Threshold, Redstone,
YYHx[1]
July 29, 2015 NT 10.0[2]
  • Windows 10 Home
  • Windows 10 Pro
  • Windows 10 Pro for Workstations
  • Windows 10 Pro Education
  • Windows 10 Enterprise
  • Windows 10 Enterprise LTSC (formerly LTSB)
  • Windows 10 Education
  • Windows 10 IoT Core
  • Windows 10 IoT Enterprise
  • Windows 10 S (now an operational mode within Enterprise and Education)[3]
See Windows 10 editions and Windows 10 version history
18362 1903 (May 2019 Update)
  • All editions except LTSB/LTSC: March updates serviced for 18 months from release date; September updates serviced for 18 months from release date (30 months for Enterprise customers). [4]
  • 2015 LTSB: Mainstream support until October 13, 2020; Extended support until October 14, 2025
  • 2016 LTSB: Mainstream support until October 12, 2021; Extended support until October 13, 2026
  • 2019 LTSC: Mainstream support until January 9, 2024; Extended support until January 9, 2029
Windows 8.1 Blue October 17, 2013 NT 6.3
  • Windows 8.1
  • Windows 8.1 Pro
  • Windows 8.1 Enterprise
  • Windows 8.1 OEM
  • Windows 8.1 with Bing
See Windows 8 editions
9600 (April 8 update)
  • Mainstream support ended on January 9, 2018
  • Extended support until January 10, 2023
Windows 8 Jupiter October 26, 2012 NT 6.2
  • Windows 8
  • Windows 8 Pro
  • Windows 8 Enterprise
  • Windows 8 OEM
See Windows 8 editions
9200
  • Unsupported as of January 12, 2016
Windows 7 Blackcomb, Vienna October 22, 2009 NT 6.1
  • Windows 7 Starter
  • Windows 7 Home Basic
  • Windows 7 Home Premium
  • Windows 7 Professional
  • Windows 7 Enterprise
  • Windows 7 Ultimate
  • Windows Thin PC
See Windows 7 editions
7601 (Service Pack 1)
  • Mainstream support ended on January 13, 2015
  • Extended support ends on January 14, 2020
Windows Vista Longhorn November 8, 2006 NT 6.0
  • Windows Vista Starter
  • Windows Vista Home Basic
  • Windows Vista Home Premium
  • Windows Vista Business
  • Windows Vista Enterprise
  • Windows Vista Ultimate
See Windows Vista editions
6002 (Service Pack 2)
  • Mainstream support ended on April 10, 2012
  • Extended support ended on April 11, 2017
Windows XP Professional x64 Edition N/A April 25, 2005 NT 5.2 N/A 3790 (Service Pack 2)
  • Mainstream support ended on April 14, 2009
  • Extended support ended on April 8, 2014
Windows XP Whistler October 25, 2001 NT 5.1 See Windows XP editions 2600 (Service Pack 3)
  • Mainstream support ended on April 14, 2009
  • Extended support ended on April 8, 2014
Windows Me Millennium September 14, 2000 4.90 N/A 3000
  • Mainstream support ended on December 31, 2003
  • Extended support ended on July 11, 2006
Windows 2000 N/A February 17, 2000 NT 5.0 Professional 2195
  • Mainstream support ended on June 30, 2005
  • Extended support ended on July 13, 2010
Windows 98 Memphis June 25, 1998 4.10 2222 A
  • Mainstream support ended on June 30, 2002
  • Extended support ended on July 11, 2006
Windows NT 4.0 Shell Update Release, Cairo August 24, 1996 NT 4.0 Windows NT 4.0 Workstation 1381 (Service Pack 6a)
  • Mainstream support ended on June 30, 2002
  • Extended support ended on June 30, 2004
Windows 95 Chicago August 24, 1995 4.00
  • Windows 95
  • Windows 95 SP1 (December 31, 1995)
  • Windows 95 OSR1 (February 14, 1996)
  • Windows 95 OSR2 (August 24, 1996)
  • Windows 95 USB Supplement to OSR2 (August 27, 1997)
  • Windows 95 OSR2.1 (August 27, 1997)
  • Windows 95 OSR2.5 (November 26, 1997)
950
  • Mainstream support ended on December 31, 2000
  • Extended support ended on December 31, 2001
Windows NT 3.51 Unknown May 30, 1995 NT 3.51 Windows NT 3.51 Workstation 1057
  • Unsupported as of December 31, 2001
Windows NT 3.5 Daytona September 21, 1994 NT 3.5 Windows NT 3.5 Workstation 807
  • Unsupported as of December 31, 2001
Windows 3.2 Unknown November 22, 1993 3.2 N/A N/A
  • Unsupported as of December 31, 2001
Windows for Workgroups 3.11 Snowball November 8, 1993 3.11 N/A N/A
  • Unsupported as of December 31, 2001
Windows NT 3.1 Unknown July 27, 1993 NT 3.1 Windows NT 3.1 528
  • Unsupported as of December 31, 2000
Windows 3.1 Janus April 6, 1992 3.10
  • Windows 3.1
  • Windows for Workgroups 3.1 (October 1992)
N/A
  • Unsupported as of December 31, 2001
Windows 3.0 N/A May 22, 1990 3.00 N/A N/A
  • Unsupported as of December 31, 2001
Windows 2.11 N/A March 13, 1989 2.11
  • Windows/286
  • Windows/386
N/A
  • Unsupported as of December 31, 2001
Windows 2.10 N/A May 27, 1988 2.10
  • Windows/286
  • Windows/386
N/A
  • Unsupported as of December 31, 2001
Windows 2.03 N/A December 9, 1987 2.03 N/A N/A
  • Unsupported as of December 31, 2001
Windows 1.04 N/A April 10, 1987 1.04 N/A N/A
  • Unsupported as of December 31, 2001
Windows 1.03 N/A August 21, 1986 1.03 N/A N/A
  • Unsupported as of December 31, 2001
Windows 1.02 N/A May 14, 1986 1.02 N/A N/A
  • Unsupported as of December 31, 2001
Windows 1.0 Interface Manager November 20, 1985 1.01 N/A N/A
  • Unsupported as of December 31, 2001

 

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What internet protocol is used to stream videos and audio on the internet?

What internet protocol is used to stream videos and audio on the internet?

  • UDP
  • IPX
  • IP
  • TCP

EXPLANATION

Drawbacks of using TCP for live video:
  1. Typically live video-streaming appliances are not designed with TCP streaming in mind. If you use TCP, the OS must buffer the unacknowledged segments for every client. This is undesirable, particularly in the case of live events; presumably your list of simultaneous clients is long due to the singularity of the event. Pre-recorded video-casts typically don't have as much of a problem with this because viewers stagger their replay activity; therefore TCP is more appropriate for replaying a video-on-demand.
  2. IP multicast significantly reduces video bandwidth requirements for large audiences; TCP prevents the use of IP multicast, but UDP is well-suited for IP multicast.
  3. Live video is normally a constant-bandwidth stream recorded off a camera; pre-recorded video streams come off a disk. The loss-backoff dynamics of TCP make it harder to serve live video when the source streams are at a constant bandwidth (as would happen for a live-event). If you buffer to disk off a camera, be sure you have enough buffer for unpredictable network events and variable TCP send/backoff rates. UDP gives you much more control for this application since UDP doesn't care about network transport layer drops.
FYI, please don't use the word "packages" when describing networks. Networks send "packets". 

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Wednesday, August 28, 2019

Simple mail transfer protocol (SMTP) commonly uses __________ as the transport layer protocol for electronic mail transfer.

Simple mail transfer protocol (SMTP) commonly uses __________ as the transport layer protocol for electronic mail transfer.

  • DCCP
  • TCP
  • UDP
  • SCTP 

EXPLANATION

The Simple Mail Transfer Protocol (SMTP) is a communication protocol for electronic mail transmission. As an Internet standard, SMTP was first defined in 1982 by RFC 821, and updated in 2008 by RFC 5321 to Extended SMTP additions, which is the protocol variety in widespread use today. Mail servers and other message transfer agents use SMTP to send and receive mail messages. Proprietary systems such as Microsoft Exchange and IBM Notes and webmail systems such as Outlook.com, Gmail and Yahoo! Mail may use non-standard protocols internally, but all use SMTP when sending to or receiving email from outside their own systems.
SMTP servers commonly use the Transmission Control Protocol on port number 25.
User-level email clients typically use SMTP only for sending messages to a mail server for relaying, typically submit outgoing email to the mail server on port 587 or 465 as per RFC 8314. For retrieving messages, IMAP and POP3 are standard, but proprietary servers also often implement proprietary protocols, e.g., Exchange ActiveSync.

 

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If you're going to secure your Exchange server, the best place for the front-end server is...

If you're going to secure your Exchange server, the best place for the front-end server is...

  • At a hosted location
  • Outside the firewall
  • The internal network
  • The internal network with ISA in the perimeter 

EXPLANATION

The generally accepted way of implementing a front end / backend configuration involves placing an ISA Server in front of the front end server.
The idea behind this configuration is that remote clients never interact directly with the front end server. Instead, the ISA Server is provided with a copy of the front end server's certificate, which allows it to impersonate the front end Exchange Server. Remote clients never actually communicate with the front end Exchange Server. Instead, remote clients communicate with the ISA server. The ISA server acts as a proxy server and forwards HTTP requests to the front end Exchange Server.
Part of the ISA server's job is to act as an application firewall for Exchange Server. What this means is that ISA server knows what types of communications are considered normal for an Exchange Server environment. It is therefore able to filter out abnormal and potentially malicious packets.
The merits of using an ISA server are sometimes debated though. The reason why this is a debated topic is that ISA Server is a software based firewall sitting on top of a Windows operating system. Some people feel that it is therefore vulnerable to the same types of attacks that any other Windows server would be.
My take on this issue is that ISA Server should be considered an essential part of a front end / back end configuration. ISA Server is not a generic firewall. It was developed by Microsoft with Exchange in mind. It contains lots of Exchange specific filtering rules that will help to keep your Exchange Server secure. At the same time though, I believe that the fact that ISA Server rides on top of a Windows operating system does pose a security threat. In my opinion, the best way to counter this threat is to place a hardware-based firewall at your network's perimeter and then have your hardware firewall forward the inbound HTTP requests to an ISA Server located behind it.

 

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