how to distinguish battery is 4.1V or 4.2V

how to distinguish battery is 4.1V or 4.2V: consumers do not distinguish between, depending on the products of batteries manufacturers specifications. Some brands of batteries are 4.1V and 4.2V common, such as A & TB (Toshiba), the domestic manufacturers is basically a 4.2V, but there are exceptions, such as Tianjin power of God 4.1V (but also by a 4.2V).

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5, the rechargeable batteries 4.1V to 4.2V happen: will increase battery capacity, feels good to use, standby time increases, but will shorten battery life. Such as the original 500, reduced to 300. Similarly, the 4.2V rechargeable batteries have also shortened life expectancy. Lithium-ion batteries is very delicate.

6, since the battery inside a protective plate, we can rest assured it: No, because the cut-off parameter is the protection board 4.35V (this is good, the bad to 4.4 to 4.5V), protection board is to meet in case, and If each overcharge, the battery will soon decay.

7, how much charge current be appropriate: In theory, the smaller the more the battery is good. But you can not order a battery charging 3 days now. GB provides low-rate charge is 0.2C (standard arbitration charge), but also to the above 1000mAh capacity battery, for example, is 200mA, then we can estimate only the battery over 5 hours to fully charge. (MAh = current capacity mA × time h)

Identification of national technical supervision departments lithium capacity, high-rate charge based on 1C to 0.2C low-rate discharge, to calculate the capacity value of time, test 5 times, with capacity of 1 end of the trial. (That is, 5 times, and if the first test to pass, and the back 4 times not to) allow for a pre-test before the cycle is to 1C constant current charge to 4.2V cease, but not behind the constant pressure to 0.01 C process, not 14 hours.

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Oracle Database Server X86 Gradually Heat Selection Guide

Based on past surveys, we know that the database Server When the selection has the following five principles: high-performance, high reliability, high scalability, security and manageability, etc.. In fact, a different database program on the server hardware requirements are different. Starting from this issue, we will focus on the most popular of several databases (Oracle/DB2/MySQL, etc.), analyze their specific needs and the server hardware market solutions.

For any enterprise, departmental-level database is already important and indispensable IT One-group, while most of these databases are produced by the Oracle Database software . Therefore, we first of all the latest on the Oracle Database 11gR2 on the server needs to do a simple analysis.

1, Oracle 11g database server component on the requirements of

Oracle 11gR2 support for unstructured data, the binary XML storage efficiency and significantly improved the speed of XML index increased by 15 times than before. On the other hand, Oracle added the results of server and client caching technology makes PL / SQL performance tripled, JAVA performance increased by 11 times. But all this means that the original equipment has been insufficient to carry the new version of the database caused performance. Experienced Oracle database administrators are aware that when dealing with Oracle products, the entire upgrade process is not only a need to upgrade to the latest version of the software and hardware upgrades are needed at the same time.

Since Oracle 11gR2 with RAC (Real Application Clusters) technology, the database can be distributed to a number of servers deployed in order to avoid make up a single server efficiency and ensure redundancy. But on the one hand the database synchronization and management problems, on the other hand also the quality of their professional DBA raised the additional demand. In contrast, administrators are more willing to use virtualization technology to deploy Oracle database, which can be better disaster recovery, fast backup, portability, performance and business continuity. This also brings the demand on the database server: virtual high-performance, Memory Large capacity and good reliability.

However, under normal circumstances, most IT departments, or follow the piece of “iron law”, that is, system design life cycle (SDLC), the existing technology or to maintain, unless the maintenance costs exceeded the cost of replacement products. We are experts in the post-face interviews with Oracle database, also found that upgrading the server when they are The first consideration is cost, performance and stability will only be considered after .

Question of cost, it is necessary that each procurement costs and operating costs, which are more and more seriously by corporate IT departments. Procurement cost point of view, is naturally more expensive RISC platforms, x86 platform occupied the unique low-cost high-performance advantages. On the other hand, the operating cost perspective, RISC environment because of their closed-source and proprietary platforms, the need for labor costs, operation and maintenance, software solutions require additional spending, while x86 platform as an open platform environment and general features , at lower cost.

This regard, is not surprising that many key business is moving from RISC + UNIX platform migration to the X86 + Linux platform. But the x86 platform has been the impression in performance RISC platforms are not as powerful, but also the stability of people’s criticism. What exactly is this?

I am China Computer Parts writer, reports some information about inside micrometer , laser micrometer.