What are Mainframes?

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Published 2017-04-04
Mainframe computers, also known as "big iron," power things from credit card processing to airline ticketing. How do they work, and what makes them different from other large-scale devices like supercomputers?

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Thanks to Connor Krukosky for his assistance with this episode.

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All Comments (21)
  • @Slarti
    I remember a network manager telling me the drives on one of our servers were 'hot swappable'. I explained that this was not the case - standing next to me in the server room he said 'look if I pull this disk out the network will stay up'. I spent the next day rebuilding the database he corrupted and the business was without IT systems for the day.
  • @amjohnson86
    As a mainframe COBOL programmer I greatly appreciate this video! Yes, I was born after 1980.
  • Did you know you can break into any mainframe by typing super fast into a green command prompt while techno music plays? It's a law of nature. Abraham Lincoln wrote an essay on it.
  • @johnmckown1267
    Wonderful and accurate. I've been working on this type of IBM system for 35 years now. This guy "gets them". There are even more redundancies than he mentioned. Automatic cpu recovery, if a CPU fails, a spare takes over and the instruction which died is automatically restarted and the user software doesn't even know it. Same with RAM memory.
  • @bentoth9555
    "Big Iron" just reminds me of the Fallout: New Vegas soundtrack.
  • I have 10 years+ developer experience on IBM mainframes. And I kind of miss the old days. For instance - back then, pressing F3 to save whatever sourcefile I was editing it usually took <1 second to save and when the system was slow maybe 3 seconds. These days saving my work to "the very large and popular cloudbased CRM system" takes 3 seconds if everything is miraculously fast - but a 30 second wait is normal.
  • @hiroshima19
    z16 is now coming out with the Telum processor, my job as a COBOL programmer has never been more secure
  • @MrFliederLP
    I once visited the IBM datacenter in Böblingen, Germany. It was a truly impressive experience to see hundreds of IBM z13's all together in one big server room. These were probably the most expensive things I've ever seen in one place!
  • @LazerLord10
    And here I thought I knew what mainframes were.
  • @Chuck_C
    For the IBM Mainframe affectionados out there. IBM announced the Z15 system, some specs are: up to 40 terabytes (TB) of RAM, up to 1536 I/O channels with over 600 FiConn channels (optical), up to 190 user processors (UP) each with 12 cores at 5.8 GHz, and a slew of specialty processors. The level of complexity can only be described as mind boggling.
  • @boetagoon
    As a mainframe system programmer, thanks for clearing up many of the misconceptions and explaining what a mainframe really is so people are better informed :) z/OS FTW :)
  • @tacticool870
    "mainframes aren't designed to run games" next up on linus tech tips "1 million dollar main frame smashed in super mario brothers emulator benchmarks by raspberry pi"
  • @TheDavidsonary
    --> Fully watch 45 min. video of some nerd dude talking about his mainframe. --> Then watch video about what a mainframe actually is. --> Realize I don't even care about any of this stuff. --> Time well spent. Please kill me.
  • @TechSecGuru
    As a former IBM SSR, I'm thankful you did a video on this @Linus, I wish more people took interest in enterprise systems like Z. Short and Quick summary, but informative for the length. Thanks!
  • @stan.rarick8556
    Thanks for being mostly correct (latest IBM is the z14 ;-) ). When I hear "Big Iron" I think of a very satisfying 46 year career.
  • @MikeFuryTech
    Seriously, one of your best videos to date. I thought everyone forgot about Mainframes. Kudos for the topic.
  • @johnlochness
    Cool video. I started as a Cobol programmer on IBM Mainframes in 1979 and worked my way up to Technical Specialist at IBM. Cobol, CICS, DB2, IMS. Left the business in 2004 to do something completely different after working for a major UK retailers on a system that ran over several mainframes and spent all day working out what people will buy in the next 21 days.
  • @Timeward76
    Linus when I hear "big iron" I think a heavy caliber six shooter.