Each operating system (OS) has to recommend it, however, as not to be too messy, you better limit what OS you are running total.
1. Application availability of
key questions: whether you will be able to choose the OS to run the application you are currently running? Currently the application is developed for it how much? How much would you pay for the cost of the application you want to run?
How many applications are available and not just a numbers game. As you know, an OS supported by tens of thousands of applications are actually games. You need to ensure that applications are able to buy, but also to confirm the cost of these applications and their support contracts should not be higher than the server - that is the traditional practice of the mainframe era. In addition, we are looking to support applications in a standard way to interact OS. For example, NT allows each application to use to transmit information between each other in OLE.
2. Platform Support
The key question: whether it supports your current clients? How does it support mobile users? The client need special software to access the server ?
There are several levels of interoperability. You can define and use a variety of different network protocols NetWare network using IPX At the lowest level, the system, and most Unix network and the Internet using TCP / IP. By default, NT to use NetBEUI. All of these OS can support other protocols, but they run their core protocols optimum efficiency. At a high level, even if the client server support low-level protocol, may still be unable to connect. A typical case is that you can run on NetWare 4.11 server Appletalk, but if a Mac for Macintosh machine without first loading the NetWare client software wanted to register to the server, you will receive an error message, tell it to the server Register unrecognizable sequences. While at the same time, NT Appletalk realization of it looks like a standard Mac server.
To select a particular type of OS integrated directory services. The starting point is: the user can not only be registered on the application server, but also be able to access any application residing on the server. For example, Unix system mainly using a Domain Name System (DNS) and Network Information Service (NIS), NetWare 4.11 using NetWare Directory Services (NDS), NT 4.0 system also uses a domain. These are difficult to reconcile with each other, but some, such as NDS, you can accept a wide variety of OS in its structure. Web appears to make this situation more controversial, some of which standardized communication protocols, such as HTTP and TCP / IP. However, for the present, cross-platform integration is the best solution, either to make a server-OS supports all protocols running the company, or some kind of agreement is the normalized (probably TCP / IP). NT appears to have expertise in running a variety of protocols, including TCP / IP, NetBEUI, IPX / SPX and Appletalk (of course there are some other), but almost any OS currently has a number of extensions, you can have the server class features.
3. Performance
The key question: How many users with a single system can support? OS of your choice whether to support symmetric multiprocessing (SMP)? Does it allow you to balance the load across multiple systems?
You can read what you want benchmark (benchmark) results, but how an OS performance in the end, also depends on how you use it. Performance is application-independent. Some benchmarks, such as Transaction Processing Council's TPC-C, represents the performance of the database system environment. While others, such as BYTEmark, it represents the performance of a particular system components. Certain aspects of the OS design shows that you can expect performance features such as multithreading can make your application must reduce the number of context switches, thereby improving performance. Preemptive multitasking feature will allow individual applications cut off each other, so that performance is more equal.
NT, OS / 2, OS / 400 and SunSoft Solaris are provided with the two functions, one is not provided with the NetWare. Next, pay attention to scalability, concrete is the SMP. All large operating systems, such as Unix, NT, NetWareSMP, OS / 2 and OS / 400 support SMP. The question is: How many of the OS CUP can handle? For example, an end user license limit NT is four, and OS / 2 can be implemented as some Unix process as up to 64. But remember, run SMP system, also you need to adjust your software.
4. Management
The key question: Can you control multiple servers from a single point? Can the server for remote access? The server is compatible with your existing management system?
The system management means different content for different people. For many people, the backup is an important part of system administration. Any OS has some built-in backup utility. However, they are not the most advanced packages, each with a different interface. If your goal is to back up their different servers from a central console, and you have been selected as Arcada's Backup exec like the software, you need to make sure that it should support the new OS. When to plan for the expansion of the network, it is necessary for you to confirm the selected OS management mechanism. If the network does not become very large, you can rely on Unix command-line interface. However, if you are responsible for a server farm, a dozen machines, you need some way to make the state of the fleet at a glance.
Some software, such as Intel's LANdesk Manager and Symantec's Norton Administrator for Networks, can help you grasp the health of the server. However, they are reluctant to support Unix and OS / 400 like OS. Further, the standard SNMP console, such as a Hewlett- Packard OpenView, the network can be provided on the case where the flow of information to you, but they do not provide information to specific system components you level. Selection management features of the basic rule is that whatever you choose what kind of OS, or ensure that it is compatible with your existing management strategy, or you yourself willing to modify existing strategies to adapt to the new OS.
5. Application Development
The key question: whether the platform you are using development tools? The OS vendor's support is only available to independent software vendor (ISV), or to support specific user? Whether it is an open API, and complete information?
Everyone is rushed to market to sell products, and therefore varies greatly. In addition to the most simple operation layer, each network will require some degree of customization. OS must have a standard OS services and industry-standard interface to support the development. Virtual memory protection, multitasking, preemptive scheduling, and other advanced features (such as threads and asynchronous I / O), have a lot of high-end development work is indispensable. To take full advantage of OS custom properties, you need a powerful set of development tools, documentation and vendor support for the OS developed in-house (this is most important). At a minimum, developers should be able to get a compiler, debugger, project management utilities and video programming tools. If you choose a server OS vendors only provide support for a large ISV, you can not find a large number of experienced developers.
Third-party vendor's support is equally important. Tools, and a full set of application programming environment is usually provided by a variety of NOS platform. Using familiar tools, developers can be handy to work at all levels.
6. Reliability
The key question: whether it supports RAID or clusters? Whether its file system log? Can hot plug components?
Protection device drivers and memory architecture is provided by the OS operating system of some reliable seal of quality, such as NT, OS / 2, OS / 400 and Unix like. However, NetWare running the application, the application can run in protected mode in a shared memory space, but the mechanism has the potential conflict with the OS. Most occur in the fault-tolerant hardware layer. Either in the form of software or implemented in hardware RAID, it is very common. The main advantage of the software is low prices, such as NT. Other fault tolerance, such as a redundant power supply, cooling fan, and the card is different depending on the different selected server. OS / 400 Solaris as well as advanced clustering solutions. IBM is working to clustering capabilities of OS / 400 (code-named Phoenix) ported to OS / 2 up. Microsoft is developing a set of API (code-named Wolfpack), a cluster of two NT machines. Digital company already has a system that can achieve NT cluster. By default, the cluster function is one of the options above operating systems, but this is really an expensive option, an average of thousands of dollars per CPU.
7. Security
The key question: Can an administrator implement password restrictions? The OS supports access control lists? Whether to support the "flight" (onthe-fly) encryption? How its Orange Book C2-level security?
Security is a very difficult problem. Different opinions, but who can not tell. In a nutshell is, if any OS install and maintain the use of a strict security policy, are likely damaged, leaking secrets. You must use an alphanumeric password, frequently changed passwords, or even consider giving important information encrypted. This shows that the OS can implement security simple. File and directory access permissions is a starting point. Each OS these two functions are implemented, but slightly different, such as Unix rather vague, and NetWare is intuitive. Or words, to specific settings and ensure its proper implementation by each person.
Audit allows you to grasp when and where people do anything. Log it produces may be large, but the information could be extremely valuable, especially when you want to track a file once the recent changes. NT with a good audit system, and very easy to use. Unix security is more and more criticism. It is open to original design, the object is now directed. If you have chosen as your application server Unix OS, you should immediately find a vendor for the latest security patches. About C2-level security has many empty words, but also nothing more, just talk. There are a number of reasons. First, C2 rating applies only to a test version of the OS, for example, NT 3.51 have a C2-level security, but the 4.0 version does not. In addition, Red Book C2-level security (indicating that the OS is a network security) refers not just this test version, but also only applies to the test hardware.
After the OS take into consideration these aspects, it is clear that it can be used as an application server OS will be how the performance. NT, Solaris, OS / 2, NetWare and OS / 400 are powerful applications - server operating system. These problems can teach you so much. After making a preliminary decision, we must also chosen OS back to the company to try to develop. It takes time, costs may be high, but the total cost will not be higher than the wrong decision, right?