Difference between ESX Vs ESXi 

It is important to discuss the terms ESX and ESXi and the difference between these. Most of you already knew as a part of Server virtualization in VMware term. Lets talk about both these terms and the difference between them.

Fig 1.1- ESX vs ESXi

ESX (Elastic Sky X)
The term ESX Server refers to Elastic Sky X, which is used to implement enterprise-level virtualization. VMware developed this virtualization platform for servers.

The virtualization kernel (VMkernel) of ESX is managed by the Service Console, an operating system.

'Bare metal' hypervisors allow software to run directly on the hardware once installed. Operating systems are not required for it to work.

The ESX service console also allowed you to download and install pretty much any agent you wanted, such as monitoring agents, backup agents, etc.

A VMkernel is essentially the brain of an ESX server, which is what the service console communicated with.

The uniformity of the server hardware makes it easy to manage, maintain, employ, and install specifications.

Other Topics:
Troubleshooting ESXi Hosts & Cisco UCS Servers

ESXi (Elastic Sky X Integrated)

Elastic Sky X integrated is known as ESXi. This is another enterprise server from VMware. This virtualization platform does not include a service console.

ESXi released vSphere 4 in 2009, which sparked the boom in virtualization. Everybody virtualized everything on-site and used ESX to operate their mission-critical workloads.

In the VMkernel, all screening and management takes place directly. Instead of using the service console, this integrated version uses the Direct Console User Interface.

It is faster to install ESXi server than ESX server when comparing ESX vs ESXi. There is less need to patch code on this server due to its reliable architecture. The architecture relies on small codes.

Additionally, ESXi is a bare-metal hypervisor that just adds a virtual barrier between the hardware and the operating system.

The integration of several servers on a small number of physical machines is a smarter use of technology made possible by ESXi. As a result, less energy, less space, and eventually less money are used.

Here is the difference 

Fig 1.2- ESX Vs ESXi

Other Topics:
Troubleshooting ESXi Hosts & Cisco UCS Servers
Adding roles and permissions in vCenter vSphere
Basics: Physical Machine to Virtual Machine Migration