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).

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 ).

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

PC can't be upgraded to Windows 10

PC can’t be upgraded to Windows 10

The May 2019 Update for Windows 10 is right around the corner and Microsoft is pre warning everyone about a known problem.  In the May 2019 Update support document (available at, Microsoft is warning Windows 10 users that have an external USB device or SD memory card attached to their computer.

If you have either an external USB device or SD memory card your computer will receive the error message:

This PC can’t be upgraded to Windows 10.

:when you try to update your computer.  The reason for the error is that the new May 2019 update may cause inappropriate drive reassignment if a Windows 10 user has an external USB device or SD memory card.

As of now, Microsoft will block the May 2019 Update on any computer with an external USB device or SD memory card.  If you want to upgrade immediately, before Microsoft resolves this bug, there is a really simple work around for the issue.  Unplug any external USB devices and SD memory card adapters and run the Windows 10 May 2019 Update.  Once the May 2019 Update is fully installed and you are back in a working Windows 10 environment, plus your external USB devices and SD memory cards back into the computer.

If you are having a problem with your Windows 10 computer and are receiving the This PC can’t be upgraded to Windows 10 error 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 Arlington Computer Repair Service, if you need computer repair in Arlington, TX please call the local office at (817) 756-6008 or schedule an appointment at

MS Paint is not going away in Windows 1903

Windows Paint going away?

Microsoft announced back in 2017 that Microsoft Paint (MS Paint) was going to be deprecated and removed in the next Creators Update  Many of us MS Paint fans and users have been worried every time we open it because it posts a deprecation warning message each time you run the application.

Brandon Leblanc, the Sr Program Manager at Microsoft just tweeted that Microsoft Paint will be included in Windows 10 for now.  Microsoft has also removed the deprecation warning message each time you run the application.

Us fans of MS Paint can celebrate for a little while longer while we resist the change that always happens with new software!

MS Paint is not going away in Windows 1903

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 or schedule an appointment at

End of Life for Windows 7

All good things must come to an end.

Windows 7 End of Life

The last day of support for Windows 7 is January 14, 2020.  After which, Microsoft will no longer provide security updates or support for PCs running Windows 7.  With over half a year until END OF LIFE day for Windows 7 you should start making plans now.  All Windows 7 computers can be upgraded to Windows 10 and as of today, Windows 7 keys are still authenticating for Windows 10 installations.

The other option is to replace your computer and have all your data migrated to your new system.  Give us a call at 1-800-620-5285 and talk with one of our support specialists to figure out which is the best option for you.

You can read more about the End of Life for Windows 7 at


Zeroday exploit for Windows and Chrome

There is a zeroday (meaning infection in the wild that was just publicly acknowledged and is infecting people) exploit for Windows 10 (and previous versions of Windows) combined with an exploit in Google Chrome .  You need to make sure to update both your Google Chrome to the latest version and apply any pending Windows 10 (or 7, 8, etc) updates.  Read more about it at:

Hard Drive Air Filters

Air Filters

Nearly all hard disk drives have two air filters. One filter is called the recirculating filter, and the other is called either a barometric or breather filter. These filters are permanently sealed inside the drive and are designed never to be changed for the life of the drive, unlike many older mainframe hard disks that had changeable filters. Many mainframe drives circulate air from outside the drive through a filter that must be changed periodically.

A hard disk on a PC system does not circulate air from inside to outside the HDA, or vice versa. The recirculating filter that is permanently installed inside the HDA is designed to filter only the small particles of media scraped off the platters during head takeoffs and landings (and possibly any other small particles dislodged inside the drive). Because PC hard disk drives are permanently sealed and do not circulate outside air, they can run in extremely dirty environments (see Figure 1-6).

FIG. 1-6  Air circulation in a hard disk.

The HDA in a hard disk is sealed but not airtight. The HDA is vented through a barometric or breather filter element that allows for pressure equalization (breathing) between the inside and outside of the drive. For this reason, most hard drives are rated by the drive’s manufacturer to run in a specific range of altitudes, usually from -1,000 to +10,000 feet above sea level. In fact, some hard drives are not rated to exceed 7,000 feet while operating because the air pressure would be too low inside the drive to float the heads properly. As the environmental air pressure changes, air bleeds into or out of the drive so that internal and external pressures are identical. Although air does bleed through a vent, contamination usually is not a concern, because the barometric filter on this vent is designed to filter out all particles larger than 0.3 micron (about 12 µ-in) to meet the specifications for cleanliness inside the drive. You can see the vent holes on most drives, which are covered internally by this breather filter. Some drives use even finer-grade filter elements to keep out even smaller particles.

Hard Disk Temperature Acclimation

To allow for pressure equalization, hard drives have a filtered port to bleed air into or out of the HDA as necessary. This breathing also enables moisture to enter the drive, and after some period of time, it must be assumed that the humidity inside any hard disk is similar to that outside the drive. Humidity can become a serious problem if it is allowed to condense — and especially if the drive is powered up while this condensation is present. Most hard disk manufacturers have specified procedures for acclimating a hard drive to a new environment with different temperature and humidity ranges, especially for bringing a drive into a warmer environment in which condensation can form. This situation should be of special concern to users of laptop or portable systems with hard disks. If you leave a portable system in an automobile trunk during the winter, for example, it could be catastrophic to bring the machine inside and power it up without allowing it to acclimate to the temperature indoors.

The following text and Table 1.3 are taken from the factory packaging that Control Data Corporation (later Imprimis and eventually Seagate) used to ship its hard drives:

If you have just received or removed this unit from a climate with temperatures at or below 50°F (10°C) do not open this container until the following conditions are met, otherwise condensation could occur and damage to the device and/or media may result. Place this package in the operating environment for the time duration according to the temperature chart.

Table 1.3  Hard Disk Drive Environmental Acclimation Table.
Previous Climate Temp.Acclimation Time
+40°F (+4°C)13 hours
+30°F (-1°C)15 hours
+20°F (-7°C)16 hours
+10°F (-12°C)17 hours
0°F (-18°C)18 hours
-10°F (-23°C)20 hours
-20°F (-29°C)22 hours
-30°F (-34°C) or less27 hours

As you can see from this table, a hard disk that has been stored in a colder-than-normal environment must be placed in the normal operating environment for a specified amount of time to allow for acclimation before it is powered on.

This is an archive of Alasir Enterprise’s MicroHouse PC Hardware Library Volume I: Hard Drives by Rhett M. Hollander ( which disappeared from the internet in 2017. We wanted to preserve Rhett M. Hollander’s knowledge about hard drives and are permanently hosting a selection of important pages from

Hard Disk Tracks, Cylinders and Sectors

All information stored on a hard disk is recorded in tracks, which are concentric circles placed on the surface of each platter, much like the annual rings of a tree. The tracks are numbered, starting from zero, starting at the outside of the platter and increasing as you go in. A modern hard disk has tens of thousands of tracks on each platter.

5.25" hard disk platter
A platter from a 5.25″ hard disk, with 20 concentric tracks drawn
over the surface. Each track is divided into 16 imaginary sectors.

Data is accessed by moving the heads from the inner to the outer part of the disk, driven by the head actuator. This organization of data allows for easy access to any part of the disk, which is why disks are called random access storage devices.

Each track can hold many thousands of bytes of data. It would be wasteful to make a track the smallest unit of storage on the disk, since this would mean small files wasted a large amount of space. Therefore, each track is broken into smaller units called sectors. Each sector holds 512 bytes of user data, plus as many as a few dozen additional bytes used for internal drive control and for error detection and correction.

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 ( 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 Drive Sector Format and Structure

The basic unit of data storage on a hard disk is the sector. The name “sector” comes from the mathematical term, which refers to a “pie-shaped” angular section of a circle, bounded on two sides by radii and the third by the perimeter of the circle. On a hard disk containing concentric circular tracks, that shape would define a sector of each track of the platter surface that it intercepted. This is what is called a sector in the hard disk world: a small segment along the length of a track. At one time, all hard disks had the same number of sectors per track, and in fact, the number of sectors in each track was fairly standard between models. Today’s advances have allowed the number of sectors per track (“SPT”) to vary significantly, as discussed here.

In the PC world, each sector of a hard disk can store 512 bytes of user data. (There are some disks where this number can be modified, but 512 is the standard, and found on virtually all hard drives by default.) Each sector, however, actually holds much more than 512 bytes of information. Additional bytes are needed for control structures and other information necessary to manage the drive, locate data and perform other “support functions”. The exact details of how a sector is structured depends on the drive model and manufacturer. However, the contents of a sector usually include the following general elements:

  • ID Information: Conventionally, space is left in each sector to identify the sector’s number and location. This is used for locating the sector on the disk. Also included in this area is status information about the sector. For example, a bit is commonly used to indicate if the sector has been marked defective and remapped.
  • Synchronization Fields: These are used internally by the drive controller to guide the read process.
  • Data: The actual data in the sector.
  • ECC: Error correcting code used to ensure data integrity.
  • Gaps: One or more “spacers” added as necessary to separate other areas of the sector, or provide time for the controller to process what it has read before reading more bits.

Note: In addition to the sectors, each containing the items above, space on each track is also used for servo information (on embedded servo drives, which is the design used by all modern units).

The amount of space taken up by each sector for overhead items is important, because the more bits used for “management”, the fewer overall that can be used for data. Therefore, hard disk manufacturers strive to reduce the amount of non-user-data information that must be stored on the disk. The term format efficiency refers to the percentage of bits on each disk that are used for data, as opposed to “other things”. The higher the format efficiency of a drive, the better (but don’t expect to find statistics on this for your favorite drive easy to find!)

One of the most important improvements in sector format was IBM’s creation of the No-ID Format in the mid-1990s. The idea behind this innovation is betrayed by the name: the ID fields are removed from the sector format. Instead of labeling each sector within the sector header itself, a format map is stored in memory and referenced when a sector must be located. This map also contains information about what sectors have been marked bad and relocated, where the sectors are relative to the location of servo information, and so on. Not only does this improve format efficiency, allowing up to 10% more data to be stored on the surface of each platter, it also improves performance. Since this critical positioning information is present in high-speed memory, it can be accessed much more quickly. “Detours” in chasing down remapped sectors are also eliminated.

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 ( 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 Drive Error Correcting Code (ECC)

The basis of all error detection and correction in hard disks is the inclusion of redundant information and special hardware or software to use it. Each sector of data on the hard disk contains 512 bytes, or 4,096 bits, of user data. In addition to these bits, an additional number of bits are added to each sector for the implementation of error correcting code or ECC (sometimes also called error correction code or error correcting circuits). These bits do not contain data; rather, they contain information about the data that can be used to correct any problems encountered trying to access the real data bits.

There are several different types of error correcting codes that have been invented over the years, but the type commonly used on PCs is the Reed-Solomon algorithm, named for researchers Irving Reed and Gustave Solomon, who first discovered the general technique that the algorithm employs. Reed-Solomon codes are widely used for error detection and correction in various computing and communications media, including magnetic storage, optical storage, high-speed modems, and data transmission channels. They have been chosen because they are easier to decode than most other similar codes, can detect (and correct) large numbers of missing bits of data, and require the least number of extra ECC bits for a given number of data bits. Look in the memory section for much more general information on error detection and correction.

When a sector is written to the hard disk, the appropriate ECC codes are generated and stored in the bits reserved for them. When the sector is read back, the user data read, combined with the ECC bits, can tell the controller if any errors occurred during the read. Errors that can be corrected using the redundant information are corrected before passing the data to the rest of the system. The system can also tell when there is too much damage to the data to correct, and will issue an error notification in that event. The sophisticated firmware present in all modern drives uses ECC as part of its overall error management protocols. This is all done “on the fly” with no intervention from the user required, and no slowdown in performance even when errors are encountered and must be corrected.

The capability of a Reed Solomon ECC implementation is based on the number of additional ECC bits it includes. The more bits that are included for a given amount of data, the more errors that can be tolerated. There are multiple trade offs involved in deciding how many bits of ECC information to use. Including more bits per sector of data allows for more robust error detection and correction, but means fewer sectors can be put on each track, since more of the linear distance of the track is used up with non-data bits. On the other hand, if you make the system more capable of detecting and correcting errors, you make it possible to increase areal density or make other performance improvements, which could pay back the “investment” of extra ECC bits, and then some. Another complicating factor is that the more ECC bits included, the more processing power the controller must possess to process the Reed Solomon algorithm. The engineers who design hard disks take these various factors into account in deciding how many ECC bits to include for each sector.

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 ( 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.

VESA Local Bus

The VESA Local Bus, also called VL-Bus or more commonly VLB, was the first local bus used on PCs. Introduced in 1992, VLB video became very popular during the heyday of the 486, in particular 1993 to 1994. VLB cards can be easily identified by their longer connectors, compared to standard ISA card slots. See here for details on the VESA local bus.

VLB video cards provide, in general, much better performance than ISA cards. This is primarily due to the fact that the 32-bit local bus used by VLB cards allows for several times more data throughput between the card and the processor than ISA allows. VLB has however had its own share of problems. In particular, VLB video cards may cause reliability problems in motherboards running at 40 or 50 MHz.

Many VLB cards are very good performers, but are hampered by their general age, along with that of the motherboards they run in; most are at least four years old and new development of better and faster chipsets is entirely in the PCI world now. Still, despite the fact that VLB is older than PCI, it can provide quite acceptable performance (although probably fewer features and less video memory). VLB is much closer to PCI than it is to ISA. Any system that will support VLB should be using it for the video card; the performance improvement over ISA is substantial in most cases.

Note: VESA Local Bus video is generally limited to 486 PCs (or other motherboards that use a fourth-generation processor). The vast majority of Pentiums and later PCs use PCI (or AGP) and do not support VLB at all, although there are some very old Pentium systems that are VLB-based.

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 ( 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.