Author Archives: kc7txm

About kc7txm

Matt Karls has a PhD in IT and is an Electrical Engineer. He works in management within the software development, IT and SEO fields and is the owner of Karls Technology. He has four kids and lives in the Phoenix metro area (when he is not travelling around to our different offices).

Hard Disk Operational Overview

As an illustration, I’ll describe here in words how the various components in the disk interoperate when they receive a request for data. Hopefully this will provide some context for the descriptions of the components that follow in later sections.

A hard disk uses round, flat disks called platters, coated on both sides with a special media material designed to store information in the form of magnetic patterns. The platters are mounted by cutting a hole in the center and stacking them onto a spindle. The platters rotate at high speed, driven by a special spindle motor connected to the spindle. Special electromagnetic read/write devices called heads are mounted onto sliders and used to either record information onto the disk or read information from it. The sliders are mounted onto arms, all of which are mechanically connected into a single assembly and positioned over the surface of the disk by a device called an actuator. A logic board controls the activity of the other components and communicates with the rest of the PC.

Each surface of each platter on the disk can hold tens of billions of individual bits of data. These are organized into larger “chunks” for convenience, and to allow for easier and faster access to information. Each platter has two heads, one on the top of the platter and one on the bottom, so a hard disk with three platters (normally) has six surfaces and six total heads. Each platter has its information recorded in concentric circles called tracks. Each track is further broken down into smaller pieces called sectors, each of which holds 512 bytes of information.

The entire hard disk must be manufactured to a high degree of precision due to the extreme miniaturization of the components, and the importance of the hard disk’s role in the PC. The main part of the disk is isolated from outside air to ensure that no contaminants get onto the platters, which could cause damage to the read/write heads.

Exploded view of a hard drive
Exploded line drawing of a modern hard disk, showing the major components.
Though the specifics vary greatly between different designs, the basic
components you see above are typical of almost all PC hard disks.
Original image © Seagate Technology Image used with permission.

Here’s an example case showing in brief what happens in the disk each time a piece of information needs to be read from it. This is a highly simplified example because it ignores factors such as disk caching, error correction, and many of the other special techniques that systems use today to increase performance and reliability. For example, sectors are not read individually on most PCs; they are grouped together into continuous chunks called clusters. A typical job, such as loading a file into a spreadsheet program, can involve thousands or even millions of individual disk accesses, and loading a 20 MB file 512 bytes at a time would be rather inefficient:

  1. The first step in accessing the disk is to figure out where on the disk to look for the needed information. Between them, the application, operating system, system BIOS and possibly any special driver software for the disk, do the job of determining what part of the disk to read.
  2. The location on the disk undergoes one or more translation steps until a final request can be made to the drive with an address expressed in terms of its geometry. The geometry of the drive is normally expressed in terms of the cylinder, head and sector that the system wants the drive to read. (A cylinder is equivalent to a track for addressing purposes). A request is sent to the drive over the disk drive interface giving it this address and asking for the sector to be read.
  3. The hard disk’s control program first checks to see if the information requested is already in the hard disk’s own internal buffer (or cache). It if is then the controller supplies the information immediately, without needing to look on the surface of the disk itself.
  4. In most cases the disk drive is already spinning. If it isn’t (because power management has instructed the disk to “spin down” to save energy) then the drive’s controller board will activate the spindle motor to “spin up” the drive to operating speed.
  5. The controller board interprets the address it received for the read, and performs any necessary additional translation steps that take into account the particular characteristics of the drive. The hard disk’s logic program then looks at the final number of the cylinder requested. The cylinder number tells the disk which track to look at on the surface of the disk. The board instructs the actuator to move the read/write heads to the appropriate track.
  6. When the heads are in the correct position, the controller activates the head specified in the correct read location. The head begins reading the track looking for the sector that was asked for. It waits for the disk to rotate the correct sector number under itself, and then reads the contents of the sector.
  7. The controller board coordinates the flow of information from the hard disk into a temporary storage area (buffer). It then sends the information over the hard disk interface, usually to the system memory, satisfying the system’s request for data.

The PC Guide
Site Version: 2.2.0 – Version Date: April 17, 2001
© Copyright 1997-2004 Charles M. Kozierok. All Rights Reserved.

This is an archive of Charles M. Kozierok’s PCGuide (pcguide.com) which disappeared from the internet in 2018. We wanted to preserve Charles M. Kozierok’s knowledge about computers and are permanently hosting a selection of important pages from PCGuide.

Hard Disk Platters and Media

Every hard disk contains one or more flat disks that are used to actually hold the data in the drive. These disks are called platters (sometimes also “disks” or “discs”). They are composed of two main substances: a substrate material that forms the bulk of the platter and gives it structure and rigidity, and a magnetic media coating which actually holds the magnetic impulses that represent the data. Hard disks get their name from the rigidity of the platters used, as compared to floppy disks and other media which use flexible “platters” (actually, they aren’t usually even called platters when the material is flexible.)

The platters are “where the action is”–this is where the data itself is recorded. For this reason the quality of the platters and particularly, their media coating, is critical. The surfaces of each platter are precision machined and treated to remove any imperfections, and the hard disk itself is assembled in a clean room to reduce the chances of any dirt or contamination getting onto the platters.


The PC Guide
Site Version: 2.2.0 – Version Date: April 17, 2001
© Copyright 1997-2004 Charles M. Kozierok. All Rights Reserved.

This is an archive of Charles M. Kozierok’s PCGuide (pcguide.com) which disappeared from the internet in 2018. We wanted to preserve Charles M. Kozierok’s knowledge about computers and are permanently hosting a selection of important pages from PCGuide.

City paid Hackers $600,000

Riviera Beach, FL recently paid ransomware hackers $600,000 to unlock their computers. The ransomware hackers had locked all the government computers and encrypted all their data. The Riviera Beach City Council gave into the ransomware hackers’ demands. They currently appear to be in the process of getting their data back right now.

The city of Riviera Beach apparently had no backups of their data. The infection appears to have started on a single computer from clicking on an email. The ransomware spread to their entire network network before it encrypted all their data.

We have seen this same sort of attack at many businesses and home user’s computers. Inside a small network running off a single router at your home or business an infected computer can spread infections across all your systems. Windows and Apple computers inherently trust other computers within your own local network. They only have minimal security protections against other systems on your own network.

All of Riviera Beach’s problems could have been solved with having a backup of their data.

What to do to protect Yourself?

Ransomware and hackers can strike at any time and the most cost effective protection is to have a backup of your entire system and data. We recommend all our clients have both an on-site and off-site backup. A $50 external USB hard drive is all you need for an on-site backup. Off-site backup services like Carbonite start at $72 a year and backup all your data instantly upon creation.

The are several reasons why you want both an on-site and off-site backup of your data. On-site backups are often targeted by ransomware attacks before they encrypt your local data so that you have no method to restore your data without paying them. On-site backups are also more susceptible to fire, theft and just general wear and tear (all hard drives eventually ware out). Off-site backups are very slow to restore from, sometimes taking up to a week to download all files if you need to do a total restore.

By having both an on-site and off-site backup you minimize your risks. On-site backups are great for a quick restore of a deleted file or going back quickly to a previous revision of a file. Off-site backups allow for a greater length of time to restore files. Backup services like Carbonite store multiple revisions of your data so you will have 5-7 snap shots over time to restore from. Off-site backups are great for a home, business or an entire city that has been hit with ransomware where you lose all access to your computers and data.

How to restore after ransomware?

After you have been hit by a ransomware attack often your best move is to reformat the computer. Additionally, all computers on your network should be turned off or isolated from one another. You will need to keep them off until you can verify that all systems are clean.

Windows 10 and MacOS allow quick methods to format the entire hard drive and start from scratch. Once you have a base Operating System up you should install anti-virus software immediately. If you have a on-site backup (hard drive, flash drive, NAS, etc) that is not encrypted or infected with the ransomware you can restore off it.

Off-site backups are the clear advantage for post ransomware cleanups. Even if encrypted data has been uploaded to their service you can restore a previous version of the file. You can often restore from as recent as the previous day’s version of a file. We often see clients after a ransomware attack and off-site backup services like Carbonite have entire teams dedicated to assisting you with restoring files after a ransomware attack.

For professional help with backups, proactive ransomware security or post ransomware cleanup, call us at 1-800-620-5285.  Karls Technology is a nationwide computer service company with offices in many major cities. This blog post was brought to you from our staff at the Phoenix Computer Repair Service. If you need computer repair in Phoenix, AZ please call our local office at (602) 445-9862.

New Chromebooks run Linux

Google just announced at their Google I/O event something amazing. Starting immediately, all new Chromebooks will include Linux and ChromeOS.

Even though Chrome OS is based on Linux, it is not a native Linux desktop environment. Chrome OS started as a fork of Ubuntu Linux. Later on Google forked Gentoo Linux and that is their current kernel base.

I thought we had Linux previously?

Last year, Google released a way to run desktop Linux within Chrome OS. There have also been methods for years to run different Linux distros with Crouton in a chroot container. But this is different, Linux will now come pre-installed and ready to launch with any new Chromebook.

What does Linux bring to Chromebooks?

Allowing Chrome OS to natively run Linux applications means more things you can do on your Chromebook. You will be able to run Linux applications directly from Chrome OS. Linux applications will now become like any other Android or Chrome OS application.

Previously, your inexpensive Chromebook that was limited to Web applications, now it can be a full fledged power house laptop. Almost any application available for Windows or MacOS have an equivalent Linux application.

Which Linux distros will be supported?

Google has already said Debian Stretch is going to be the first Linux distro. You can already get a near production version of this out. Subscribe to the Beta or Dev channel release of Chrome OS for the PixelBook and you can play with this new feature.

Google says security will still stay at the forefront of Chrome OS. Chrome OS uses Linux’s kernel based VM. All Linux distros will run in VM sandboxes. This will block Linux applications from accessing or controlling your chromebook. This means you can now use your Chromebook for more serious use like software development or security testing.

The mainstream Chrome OS release channel should support Linux distros by end of July 2019. You can switch to the Beta or Dev release channel if you would like to experience this today. You can expect to be using Linux applications some time soon!

For help with your Chromebook or any other Linux computer issues, call us at 1-800-620-5285.  Karls Technology is a nationwide computer service company with offices in many major cities. This blog post was brought to you from our staff at the Phoenix Computer Repair Service, if you need computer repair in Phoenix, AZ please call the local office at (602) 445-9862.

What is Wi-Fi 6?

Wi-Fi 6, originally known as 802.11ax, is an expansion of 802.11ac, which is now called Wi-Fi 5. Are you confused yet? Okay, let’s start by defining how the Wi-Fi Alliance is redefining and more importantly renaming the last twenty years of Wi-Fi naming conventions.

The Wi-Fi Alliance is international organization that define the specifications for the various different wireless standards. They create rules and define how different pieces of wireless equipment can talk to one another so manufacturers can make wireless devices that all speak to one another.

Thus, over the years not everyone has conformed to all the standards and that’s why in years past you had to purchase only Netgear MIMO wireless equipment to work with Netgear routers (or insert any other brand that didn’t want to conform to published standards).

The Wi-Fi Alliance has decided that naming each standard based on their specification policy name within the IEEE’s standards policies was confusing to consumers. So they have decided to rename the new standard from 802.11ax to Wi-Fi 6 and retroactively rename all the previous standards at the same time.

New names for Wi-Fi standards

  • 802.11b launched in 1999 is now called Wi-Fi 1
  • 802.11a launched in 1999 is now called Wi-Fi 2
  • 802.11g launched in 2003 is now called Wi-Fi 3
  • 802.11n launched in 2009 is now called Wi-Fi 4
  • 802.11ac launched in 2013 is now called Wi-Fi 5
  • 802.11ax which was just finalized this year (2019) is the new Wi-Fi 6

How is 802.11b before 802.11a?

So this is a little confusing but essentially both the a and b specification of 802.11 were adopted at the same time. The 802.11a amendment allows for higher speeds and more channel selection but it cost significantly more than 802.11b did back in 1999. 802.11a was the first user of the nice and empty 5.7 GHz band. 802.11b was the first user of the HIGHLY congested 2.4 GHz band (which has held all wireless development back for years).

Both the a and b standards were available to manufactures in 1999 and the b standard was much less expensive to produce, that was the primary standard for years (and the first to market in 1999). 802.11b works at a maximum speed of 11 Mbit/s and had only 3 independent channels (there are 11 total, but all but 3 overlap one another….this is still true today if you are on a 2.4 GHz wireless network).

802.11a works at a maximum speed of 54 Mbit/s and has 12 independent channels (none of which overlap). 802.11a is obviously the superior standard, thus why the Wi-Fi Alliance rebranded it as Wi-Fi 2 even though it was not an evolution of Wi-Fi 1.

What does 802.11ax mean?

For any wireless nerds (like me) the IEEE 802 is the standards dealing with Local and Metropolitan networks. the .11 is the eleventh defined standard which deals with wireless communications. Every amendment to the standard is given a new letter. Initially the first wireless specification to be standardized was 802.11a, the second was 802.11b. After a dozen years of this the IEEE ran out of characters and switched to two character standards with 802.11ac (much like Excel when you pass column Z and the next one is AA). The current standards have defined specifications up through 802.11ay (which is a 60 GHz wave spectrum system).

Will old equipment work on Wi-Fi 6 wireless networks?

Wi-Fi 6 is just like all previous versions of 802.11x wireless networks in regards to backwards standard compatibility. You will be able to use your 802.11ac (Wi-Fi 5) or previous wireless devices on the new network at the reduced performance level they operate at. Wi-Fi 6 does a better job as isolating older equipment on your wireless network so you will not see as much degradation of your bandwidth using older wireless devices like you have seen in previous versions.

Do I need to get a Wi-Fi 6 router now?

There are only a few routers out that conform to 802.11ax. The Netgear AX8 is probably the best consumer model on the market that we have setup for a client. Expect other brands to start releasing 802.11ax / Wi-Fi 6 routers over the rest of 2019. If you need to replace your router you may as well upgrade to Wi-Fi 6 today since all new wireless equipment will be based on the standard soon.

If you would like to upgrade to Wi-Fi 6 or have any issues with your wireless network and would like to have a professional computer service company consult with you and set it up for you, call us at 1-800-620-5285.  Karls Technology is a nationwide computer service company with offices in many major cities.  This blog post is brought to you from our staff at the Aurora Computer Repair Service, if you need computer repair in Aurora, CO please call the local office at (720) 441-6460.

Dell

Dells vulnerable to remote hijack

A security flaw in the DellSupportAssist that comes preinstalled on all Dell computers could allow a remote hijack of your computer. The attack exposes a vulnerability DellSupportAssist has with remote code execution.

How the remote hijack works

A Dell computer user would have to go to a web page where the attackers would place compromised Javascript. The Javascript can trick the DellSupportAssist into thinking Dell is trying to remote into the computer to fix a problem. The attacker has to be on your same network to then take control of your computer. Attacks on home computers are unlikely (unless other computers are already compromised). Attacks emanating from public wifi (coffee shops, large public venues), hotels and on corporate networks are much more likely.

Proof of concept attack already published

A proof of concept showing how to implement the attack was published on Github several days ago. The attack and vulnerability, called
CVE-2019-3719, is already live and can now be reproduced by anyone.

What Dell Computers are affected?

All recent and old Dell computers that have not disabled the built in DellSupportAssist are vulnerable to this attack. Dell is working on a security patch / update for DellSupportAssist but we would recommend that you disable the DellSupportAssist service for now.

If you have a Dell computer and would like to have a professional computer service company verify your system is secure, call us at 1-800-620-5285.  Karls Technology is a nationwide computer service company with offices in many major cities.  This blog post is brought to you from our staff at the Lakewood Computer Repair Service, if you need computer repair in Lakewood, CO please call the local office at (720) 441-6460.

High CPU Nvidia Bug Fixed

Nvidia has just released Nvidia driver version 430.53 which is a hotfix to resolve a high CPU problem. We have seem several clients complain about desktop videos flickering. The flickering happens in a variety of configurations (moving a video from one monitor to another, when launching a game, on benchmarking) but in all cases we have seen a very high CPU utilization from NVDisplay.Container.exe.

The new Nvidia driver v430.53 will also add Windows 10 May 2019 Update support. NVidia engineers have confirmed in the Nvidia GeForce Forums that they were able to reproduce the issue after driver version 430.39 (although we have seen examples of it for several weeks now). They state this hotfix was made specifically to address the high CPU problem and ensure May 2019 Update compatibility.

If you are experiencing high CPU issues with your Nvidia video card and would like some assistance, please give us a call at 1-800-620-5285.  Karls Technology is a nationwide computer service company with offices in many major cities.  This blog post is brought to you from our staff at the Plano Computer Repair Service, if you need computer repair in Plano, TX please call the local office at (469) 299-9005.

Microsoft kills off some PCs

The new May 2019 Update will expand the list of PCs that will not be able to upgrade beyond their current version of Windows 10. Previously Microsoft removed support for Intel Clover Tail processors (see this TechNet note ). The new update will expand the list of Atom processors and other lower end computers that will not be able to support updates beyond the current one.

Microsoft has moved to software as a service model so if you cannot upgrade your version of Windows it will stop receiving support and updates after 18 months. The problem with this if those computers would have stayed on Windows 8 or 8.1 they would receive support and updates until 2023.

If your computer needs to be upgraded and would like some assistance, please give us a call at 1-800-620-5285.  Karls Technology is a nationwide computer service company with offices in many major cities.  This blog post is brought to you from our staff at the Scottsdale Computer Repair Service, if you need computer repair in Scottsdale, AZ please call the local office at (480) 240-2960 or schedule an appointment at www.scottsdalecomputerrepairservice.net.

Roaming User Profiles will reset

If you are a mobile computer user that uses a Roaming User Profile look out for the new update of Windows 10. Roaming Users that customize your start menu settings or any operating system settings will be reset after updating to May 2019 Update of Windows 10.

Microsoft lays out a work around in a support article ( https://support.microsoft.com/en-us/help/4493782/customized-start-menu-not-persisting-after-upgrade-in-windows-10 ) published today. The work around only works if the Start Menu customizations that are stored locally and have not been deleted due to a group policy.

This update is part of the LCU (latest cumulative update) released today for older versions of Windows 10 (versions 1703, 1709 and 1803).

If you use a Roaming User Profile and would like some assistance, please give us a call at 1-800-620-5285.  Karls Technology is a nationwide computer service company with offices in many major cities.  This blog post is brought to you from our staff at the Frisco Computer Repair Service, if you need computer repair in Frisco, TX please call the local office at (469) 299-9005 or schedule an appointment at www.friscocomputerrepairservice.com.

Passwords in Windows are changing

Microsoft has published a draft security revision for Windows 10 version 1903 (May 2019 Update) that changes security requirements for Windows 10 desktop users and Windows Server 2016 / Windows Server 2019 (read the new draft at https://blogs.technet.microsoft.com/secguide/2019/04/24/security-baseline-draft-for-windows-10-v1903-and-windows-server-v1903/ ).

The biggest change in the draft security revision is that Microsoft is dropping the password expiration policy. Previously, Microsoft had set the default password expiration period at 90 days.

Microsoft explained the purpose behind changing the password expiration policies in the draft security revision:


When humans pick their own passwords, too often they are easy to guess or predict. When humans are assigned or forced to create passwords that are hard to remember, too often they’ll write them down where others can see them. When humans are forced to change their passwords, too often they’ll make a small and predictable alteration to their existing passwords, and/or forget their new passwords.

Microsoft TechNet

Which makes perfect sense. The purpose of password expiration policies are to force password changes assuming that someone’s password will frequently be compromised. If a password never gets compromised, there is no need to change the password regularly.

There are a handful of other important changes coming in the May 2019 Update of Windows 10. Some of the more notable changes are:

  • Removing multicast name resolution
  • Removing Data Execution Prevention for Windows Explorer
  • Removing Heap termination on corruption
  • Limiting NetBT NodeType to P-node
  • Creating a svchost.exe mitigation policy
  • Removing BitLocker drive encryption ciphers
  • Removing built-in Windows admin account
  • Removing built-in Windows guest account
  • Adding Kerberos authentication audit settings

If you are having security problems or any other issue with your Windows 10 computer and would like some assistance, please give us a call at 1-800-620-5285.  Karls Technology is a nationwide computer service company with offices in many major cities.  This blog post is brought to you from our staff at the Arvada Computer Repair Service, if you need computer repair in Arvada, CO please call the local office at (720) 441-6460 or schedule an appointment at www.arvadacomputerrepairservice.com.