1.服务器：
顾名思义，服务器基本上是由硬件或具有较高可靠性或质量的硬件连接到局域网，广域网和Internet的计算机或PC。它只是通过计算机网络访问，保留和传输来自其他计算机的所有数据和文件。
示例： Linux，NetWare，Web服务器等。
2.主机：
顾名思义，大型机是一类计算机，可以处理和控制大量连接的用户，处理大量事务并提供更可靠的性能。它与运行可扩展软件以及处理大规模并行操作很好地结合在一起。它被认为是每秒执行数百万个事务的最佳平台。
示例： IBM zSeries，System z9，System z10，NonStop等。
服务器和大型机之间的区别：
|
Server |
Mainframe |
|---|---|
| It controls and handle access to hardware, software, and other resources on network. | It controls and handle hundred and thousands of connected users simultaneously. |
| It provides centralized storage for programs, data, and information. | It provides storage for instructions, information, and huge amount of data. |
| These are small in size as compared to mainframe therefore require less floor space. | These are huge in size as compared to server therefore requires more floor space. |
| It is more cost effective as compared to mainframes. | It is more costly as compared to servers as its initial cost, cost of running, and maintenance cost is very high. |
| It provides various functionalities such as sharing data or resources among users, performing computation for client. | It provides e-commerce and mobile world more reliable, available and scalable way to perform their basic business functions. |
| They are designed to not only help business with data storage but also to improve efficiency and productivity. | These computers are designed to handle large-scale processing, data storage and other tasks. |
| It cannot handle huge volume of transactions, high reliability and different types of workloads. | It supports and handles huge volume of transactions, high reliability and support different types of workloads. |
| It is used in digital applications such as Big data, Edge, Cloud applications and IoT applications, etc. | It is used in Banking applications, high volume OLTP (Online Transaction Processing) applications, back-end systems, etc. |
| Cloud options are limitless and available in huge quantity. | Cloud options are limited in mainframes. |
| Performance of server get impacted if any components are overloaded. | Performance of mainframes does not get affected even if memory is overloaded. |