What is the maximum number of USB devices a host controller can handle?

What is the maximum number of USB devices a host controller can handle?

• 128
• 155
• 64
• 127 

 

EXPLANATION

At 7 bits long, a single USB Host Controller can allow up to 127 (2^7 – 1 Host Controller) connected devices.

USB hubs can be cascaded up to seven times, the maximum number of user devices is reduced by number of hubs. So, with 19 hubs attached, the maximum number of available devices is reduced 127 − 19 = 108.

SOURCE

https://en.wikipedia.org/wiki/USB_hub (Physical Layout section)

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What type of DNS record is used by the Sender Policy Framework (SPF)?

What type of DNS record is used by the Sender Policy Framework (SPF)?

• TXT
• MX
• A
• CNAME 

 

EXPLANATION

Sender Policy Framework (SPF) is a simple email-validation system designed to detect email spoofing. The SPF is an open standard specifying a technical method to prevent sender-address forgery. SPF allows administrators to specify which hosts are allowed to send mail on behalf of a given domain by creating a specific SPF record (or TXT record) in the Domain Name System (DNS). Mail exchangers use DNS records to check that mail from a given domain is being sent by a host sanctioned by that domain's administrators.

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What's a network segment for public-facing servers that's separated from a private, trusted network by a firewall?

What's a network segment for public-facing servers that's separated from a private, trusted network by a firewall?

• DMZ
• NSA
• VPN
• ATA 

EXPLANATION

A DMZ, or demilitarized zone, is a physical or logical subnetwork that contains and exposes an organization's external-facing services to a larger and untrusted network, usually the Internet. The purpose of a DMZ is to add an additional layer of security to an organization's local area network (LAN).

SOURCE

http://www.ciscopress.com/articles/article.asp?p=1823359

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To avoid data corruption, which of the following should you do before performing fsck on a file system?

To avoid data corruption, which of the following should you do before performing fsck on a file system?

• Reboot the machine
• Create a new data partition
• Unmount the file system
• Ensure the file system is mounted 

 

EXPLANATION

The fsck command is used to check and repair one or more Linux file systems. Running fsck on a mounted file system can cause data or disk corruption. Instead, you can do one of the following:
(a) Take down system to single user mode and unmount the system
(b) Boot from the installation CD

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On systems running MS Windows, which OS service manages the print queue?

On systems running MS Windows, which OS service manages the print queue?

• Spooler
• LPD
• RAW daemon
• Print manager 

 

EXPLANATION

The spooler service manages print jobs on Windows OS PCs.  Sometimes this service can get "stuck" and otherwise interrupt printing.  A quick and effective troubleshooting idea is to simply stop and restart the service.  This is done through an elevated command prompt:

net stop spooler

Then restart using the following:
net start spooler

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Which of the following Powershell commands would give User2 access to User1's calendar? User2 does not currently have access to anything of User1's

Which of the following Powershell commands would give User2 access to User1's calendar? User2 does not currently have access to anything of User1's

• Add-MailboxFolderPermission -Identity User1@contoso.com:\Calendar -User User2 -AccessRights Owner
• Set-MailboxFolderPermission -Identity User1@contoso.com:\Calendar -User User2 -AccessRights Owner
• Set-MailboxPermission -Identity User1@contoso.com:\Calendar -User User2 -AccessRights Owner
• Add-MailboxPermission -Identity User1@contoso.com:\Calendar -User User2 -AccessRights Owner 

 

EXPLANATION

There are two things to notice.  First is that you're trying to give new permissions to User2 and not change current permissions of User2 within User1's mailbox.  So we'll want to use Add instead of Set.  Set is used to change permissions if a user already has some sort of permissions within the mailbox.
The second thing is that the calendar is a folder within the mailbox.  We don't want User2 to be able to read User1's emails, so we'll do Add-MailboxFolderPermission instead of Add-MailboxPermission.

SOURCE

https://technet.microsoft.com/en-us/library/dd298062(v=exchg.160).aspx

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In Windows, If you close a tab in Firefox/Chrome/IE, what key command will re-open it for you?

In Windows, If you close a tab in Firefox/Chrome/IE, what key command will re-open it for you?

• Ctrl-Shift-T
• Ctrl-T-O
• Ctrl-Alt-T
• Ctrl-Alt-O-T 

 

EXPLANATION

When you realize you just closed that browser tab that you have kept open for the last 4 days... just in case. You can easily now just  type "Ctl - Shift - T" to get it back.

SOURCE

http://www.slate.com/blogs/future_tense/2013/08/22/keyboard_shortcut_helps_recover_lost_browser_tabs.html

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