MAINFRAMES BEING THE OLDEST TECHNOLOGIES NO OTHER COULD REPLACE IT...

1960's	Burroughs B5000 mainframe introduced. The system can be considered the first of the "third generation" of computer systems. The most remarked-upon aspects are its use of a hardware-managed stack for calculation, and the extensive use of descriptors for data access. It included virtual memory -- perhaps the first commercial computer to do so -- as well as support for multiprogramming and multiprocessing.
1964	CDC (Computer Data Corp.) 6600 shipped; 100 nsec cycle time.
	First GE Time-sharing operation at Dartmouth College of the DTSS Dartmouth time-sharing system on a GE-265 (GE-225 + Datanet-30)
	IBM announces the 360 family of computer systems.
	The Burroughs B5500, appeared. It also had multiprogramming and virtual memory capabilities, but was three times faster than the B5000
1965	IBM ships the midrange 360 model 40 computer which had COBOL and FORTRAN programming languages available as well as the stock Basic Assembly Language (BAL) assembler.
	Introduction of GECOS-II, a multi-programming operating system for the GE-600
1966	The Burroughs B6500, which was actually an improved version of the B5500.
1967	First IBM 360/Model 91 shipped to NASA GSFC.
1969	First shipment of the CDC 7600 computer system.
	First shipment of IBM 360 Model 85. The 360 family was intended to have 3 operating systems: DOS/360 operating system for the small machines. It could run two "real-time" sessions and one batch session. OS/360 operating system for the midrange and high end. TSS/360 operating system for Time-sharing Multi-user system
	Introduction of Honeywell model 115 in the H-200 product line. The line was renamed H-2000 after models 115/2, 1015 and 2015 introduced in January 1971, and model 2020 and 2030 in December 1972 after the GE merger. The line was eventually merged into Series6 0 NPL through a H-200 mode (emulator) on level 64.
	Introduction of GE-655 that was better known as H-6000 after 1970.
1970	Burroughs announces the 700 series. The first B6700 computer systems were installed during 1971. It was the first Burroughs machine with dynamic linking of programs at runtime. The B6700 line started out with one CPU and one i/o processor and could be expanded up to a maximum of three CPUs and two i/o processors.
	Formal acquisition of Bull-General Electric by Honeywell. BGE takes the name of Honeywell-Bull.
	IBM announces a family of machines with an enhanced instruction set, called System/370. The 370s proved so popular that there was a two-year waiting list of customers who had ordered a systems.
	A giant dies: Announcement of the cession of the world-wide GE computer business, except time-sharing to Honeywell.
1971	US Air Force orders several Honeywell H-6000 WWMCCS (World Wide Military Command and Control System), a $3.5M contract.
	First shipments of IBM S/370 Models 155 and 165 as well as the S/360 Model 195.
1973	Introduction of virtual memory on IBM S/370 Models 158 and 168.
1975	Amdahl 470 V/6 computer system delivered to NASA.
1977	The Burroughs Scientific Processor was developed, and announced.
	IBM 3033 computer system announced
1979	The Burroughs 900-level systems were introduced.
1985	The most powerful IBM computer system of its time, the 3090 high-end processor of the IBM 308X computer series incorporated one-million-bit memory chips, Thermal Conduction Modules to provide the shortest average chip-to-chip communication time of any large general purpose computer. The Model 200 (entry-level with two central processors) and Model 400 (with four central processors) IBM 3090 had 64 and 128 megabytes of central storage, respectively. At the time of announcement, the purchase price of a Model 200 was $5 million. A later six-processor IBM 3090 Model 600E, using vector processors, could perform computations up to 14 times faster than the earlier four-processor IBM 3084.
1990	The ES/9000 models came out with fiber-optical I/O channels (ESCON), and IBM began using the name System/390. The ES/9000s exploited new technologies, such as high-speed fiber optic channels with IBM's new ESCON architecture, ultra-dense circuits and circuit packaging that provided higher performance, extended supercomputing capabilities and twice the processor memory previously available. The line spanned a 100-fold performance range increase from the smallest (model 120) to the most powerful (model 900 six-way multiprocessor). Basic purchase prices for the air-cooled processors of ES/9000 ranged from approximately $70,500 to $3.12 million. Basic purchase prices for the water-cooled models ranged from $2.45 million to $22.8 million.
1999	IBM releases a new generation of S/390.
2002	The S/390 G5/G6 enterprise server family has up to 256 channels, from 2 to 8 Cryptographic Coprocessors, from 8 to 32 Gigabytes of memory, and can run under OS/390, MVS, VM, VSE, or TPF operating systems. It can also host an unbelievable amount of hard drive storage. Let's see a PC match that!
2004	The 3/4 ton IBM eServer zSeries 890, dubbed the "Baby Shark" can host up to 32 GBytes of memory. The four PCIX Crypto Coprocessor (and optional PCI Crypto Accelerators) on the z890 have seven engine levels, giving a total of 28 capacity settings overall. With it's advanced virtualization technology the 64-bit z890 can run several operating systems at the same time including z/OS, OS/390®, z/VM®, VM/ESA®, VSE/ESA, TPF and Linux for zSeries and Linux for S/390®. The z890 is upgradeable within z890 family and can also upgrade to z990 from select z890 configurations. Configured with the new Enterprise Storage Server Model 750 which handles from 1.1TB up to 4.6TB of data, the x890 makes an awesome server.
2007	IBM produces the Blue-Gene/P, a system capable of a petaflop (1,000,000 gigaflops or 1,000 teraflops). It sports 73,728 processors comprised of four cores each of IBM’s 850MHz PowerPC 450, resulting in 294,912 cores. The system can be scaled to nearly three times that size, resulting in a 3 petaflop capability and is all hooked up via a high-end optical network.