Most laptops today use lithium Ion (Li-ion) batteries. Overcharging Li-ion batteries is not a problem and does not affect the battery life span. These batteries can be charged 300 to 500 times, and they have an internal circuit to stop the charging process at full charge. The control system prevents overcharging, which can cause the lithium ion battery to overheat and potentially burn. This is why the Li-ion batteries are more expensive. The only way for the Li-ion battery to overcharge is if the charging system malfunctions, and then the battery will heat up while in the charger. If you don’t plan to use your laptop for long period of time, you can extend the life of your lithium ion laptop battery by storing it with a 50 percent charge. A fully discharged battery left for a long period of time will lose its charging capacity. Fully charged batteries discharge when they are left unused, and will lose effectiveness. This is why it is recommended to discharge a Li-ion battery until it is almost out before shutting down. Running a Li-ion battery down completely will diminish capacity. Keep the
It was February 1981. Nearly half of the Apple II engineering team at Apple Computer had been fired the previous day, and now the company’s CEO, Steve Jobs, was peering over the wall of programmer Andy Hertzfeld’s cubicle.
Hertzfeld was typing code for Apple II’soperating system when Jobs rounded the corner, yanked the computer’s power cord out of the socket and carted the machine — with Hertzfeld in tow — from the corporate campus to a small office overlooking a Texaco station in Cupertino, Calif.
Hertzfeld wasn’t fired; he was promoted.
He would spend his days authoring code for Apple’s new Macintosh project [source: Hertzfeld]. The team had only a few months to create a new operating system that would be faster and more efficient — and become the predecessor of today’s iMacs.
The abrupt reassignment and truncated schedule were a workplace phenomenon Apple employees knew as a “reality distortion field.” This Star Trek term was used to describe Jobs’ ability to convince nearly anyone to do nearly anything — and deliver it according to an unrealistic timetable [source: Hertzfeld].
Regardless of whether Jobs
One of the best ways to keep a keyboard in top condition is periodic cleaning. As preventive maintenance, you should vacuum the keyboard weekly, or at least monthly. When vacuuming, you should use a soft brush attachment to dislodge the dust. Also note that some keyboards have keycaps that come off easily, so be careful when vacuuming; otherwise you may have to dig the keys out of the vacuum cleaner. I recommend using a small, handheld vacuum cleaner made for cleaning computers and sewing machines; these have enough suction to get the job done with little risk of removing your keytops.
You also can use compressed air to blow the dust and dirt out instead of using a vacuum. Before you dust a keyboard with the compressed air, however, power off the computer, unplug the keyboard, and turn it upside down so the particles of dirt and dust collected inside can fall out.
On most keyboards, each keycap is independently removable, which can be handy if a key sticks or acts erratically. For example, a common problem is a key that does not work every time you
One topic you might hear people discussing when they’re talking shop about computers is how much random access memory (RAM) they need to add to their computer. Up to a point, adding RAM will normally cause your computer to seem faster on certain types of operations. RAM is important because it eliminates the need to “swap” programs in and out.
When you run a program such as a word processor or an Internet browser, the microprocessor in your computer pulls the executable file (.exe) off the hard disk and loads it into RAM. Large programs like Microsoft Word or Excel use large amounts ofmemory. The microprocessor also pulls in a number of shared dynamic link libraries (DLLs) — shared pieces of code used by multiple applications. The DLLs take many more megabytes.
Then the microprocessor loads in the data files at which you want to look, which might total several megabytes if you are looking at more than one document or browsing a page with a lot of graphics. So a big application can easily take 100 megabytes of RAM or more, which can slow your system down significantly if there isn’t enough memory. On your
Few argue that the next generation of computers will be nearly invisible, meaning that they will blend in with everyday objects. Flexible ink-like circuitry will be printed onto plastic or sprayed onto various other substrates, such as clothes. One of the scientists leading this printable computer revolution is Joseph Jacobsonof MIT Media Lab’s Nano Media Group. Jacobson has said that his group will be able to produce a simple printed microprocessor in late 2001 or early 2002. He also foresees being able to eventually produce a printed chip that could rival anIntel Pentium processor.
Jacobson’s group has already succeeded in using an ordinary Hitachi ink jet printer to make several components for a printable computer. Using a nanoparticle-based inkmade from suspending nano-size semiconductor particles in a liquid, researchers spray the components onto a plastic substrate. Here’s a look at some of the printed components the MIT group has made with this process:
- Thermal actuators — An actuator is a sensor that causes a device to be turned on, off, adjusted or moved. In a thermal actuator, heat is used to cause the expansion of components to create movement.
- Linear-drive motors — This type of motor is similar
Virtually all PCs built since 1996 use a flash ROM to store the BIOS. A flash ROM is a type of EEPROM chip you can erase and reprogram directly in the system without special equipment. Older EPROMs required a special ultraviolet light source and an EPROM programmer device to erase and reprogram them, whereas flash ROMs can be erased and rewritten without you even removing them from the system. On some systems, the flash ROM is not a separate chip but instead might be incorporated into the southbridge chip.
Using flash ROM enables you to load the upgrade into the flash ROM chip on the motherboard without removing and replacing the chip. Normally, these upgrades are downloaded from the manufacturer’s website. Depending on the design, some update programs require that you place the software on a bootable optical disc, whereas others configure the program to run on the next startup (before Windows loads), and still others actually run in Windows as a Windows application.
Some systems allow the flash ROM in a system to be locked (write-protected). In that case, you must disable the protection before performing an update—usually by means of a jumper or switch.
These are some of the most frequently asked troubleshooting questions I receive, along with the solutions that typically address them.
When I power the system on, I see the power LED light and hear the fans spin, but nothing else ever happens.
The fact that the LEDs illuminate and fans spin indicates that the power supply is partially working, but that does not exclude it from being defective. This is a classic “dead” system, which can be caused by almost any defective hardware component. In my experiences I’ve had more problems with power supplies than most other components, so I recommend immediately using a multimeter to measure the outputs at the power supply connectors and ensure they are within the proper 5% tolerances of their rated voltages. Even if the voltage measurements check out, you should swap in a high-quality, high-power, known-good spare supply and retest. If that doesn’t solve the problem, you should revert to the bootstrap approach I mentioned earlier, which is to strip the system down to just the chassis/power supply, motherboard, CPU (with heatsink), one bank of RAM (one DIMM), and a video card and display. If the motherboard now starts, begin
USB storage devices, such as flash memory “thumb” drives, have long been known to be a potential security risk. USB drives have been used to spread many types of malware, so it’s not surprising that blocking USB storage devices is a typical Group Security Policy setting in many corporate installations of Microsoft Windows. Most types of infections carried in the storage area of USB drives can be detected and removed with anti-malware software. Unfortunately, research announced at the July BlackHat 2014 security conference revealed that the security risks of USB go far beyond storage devices.
Security researchers Karsten Nohl and Jakob Lell of SR Labs discovered that the firmware in many types of USB devices, including flash drives, webcams, keyboards, and so on, can be rewritten to contain malware that cannot be detected with conventional anti-malware apps.<, which they dubbed “BadUSB,” (see https://srlabs.de/badusb/) could be used to take over the connected device, use it as a relay point for data, enter commands as if they’re being typed by the user, and perform many other types of malware attacks. Once a system is infected with USB firmware-based malware, it can infect the next USB