Basic knowledge of OS and Linux

Open Systems (operlating System) abbreviated OS: Open systems are a term widely used in computer architectures, computing systems, software and communications systems. Open systems encourage the development of compatible vendor products. Customers can benefit from open systems because they can choose from a wide range of products that work with the system, and more importantly, easily interconnect with other vendors ' products. An open environment provides standard communication facilities and protocols, or provides a way to use different protocols. Computer Society has put more pressure on manufacturers to be open because they must publicly promise that they will be able to work with existing systems when selling products.

General purpose: Hardware drivers, process management, memory management, network management, security management

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System call Syscall: A set of program interfaces or application programming interfaces (application programming Interface,api) consisting of all system calls provided by the operating system implementation. Is the interface between the application and the system.

Programming Hierarchy:

Hardware specifications

System calls

Library calls

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ABI (Application binary Interface, Application binary excuse): Describes the low interface between an application and the operating system, between an application and its libraries, or the components of an application.

APIs (application Programming Interface, application programming interfaces) are pre-defined functions designed to provide the ability of applications and developers to access a set of routines based on a piece of software or hardware without having to access the source code. Or understand the details of the internal working mechanism.

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CPU Architecture Type: (Focus on X86, X64, ARM)

• x86 is the standard abbreviation for Intel processor-based systems. X has nothing to do with the processor, it is a simple wildcard definition for all *86 systems, is a number for an Intel general-purpose computer series, and also identifies a set of generic sets of machine instructions, since earlier Intel's CPU numbers are numbered like 8086,80286. Since this entire series of CPUs are directive compatible, they all use X86 to identify the set of instructions used today's Pentium, P2,P4, Celeron series are supported X86 instruction system, so all belong to the X86 family

  
  

• 64-bit technology is relative to 32-bit, this bit refers to the CPU GPRs (general-purpose registers, general register) data width is 64 bits, 64-bit instruction set is to run 64-bit data instructions, This means that the processor can run 64bit data at a time. 64bit processors are not available now, in high-end RISC (reduced instruction set Computing, thin instruction set computer) very early 64bit processors, such as Sun Company's Ultrasparcⅲ, IBM's POWER5, HP company Alpha, etc.

  
  

• ARM processor is the first RISC microprocessor designed by Acorn Limited for the low budget market. Earlier known as Acorn RISC Machine. The ARM processor itself is a 32-bit design, but it also comes with a 16-bit instruction set, typically saving up to 35% compared to an equivalent 32-bit code, but retains all the benefits of a 32-bit system.

Basic knowledge of OS and Linux