Random A+ stuff

a+In about 3 days I’ve crammed some 40 hours of video, taking notes, then studying them. Oh and then immediately take the exam of course. All videos are from my friends at Pluralsight and in this case from the CompTIA A+ certification path they offer. I’ve always liked learning by videos but never took the time to do so (only for an old love of mine, poker).

But now that I’ve got a lot of time on my hands because I’ve almost died last year, I’m really loving learning by video! This certification path is about 95% of material that I already know but there are some nice bits and pieces that I had to brush off and a few that are new actually.

Some random A+ ramblings

  • The parity bit added to every byte of RAM can detect errors. I found it funny that when such an error is detected, your machine crashes. ECC Ram, which stands for Error Correcting Code Random Access Memory, detects and corrects the error.
  • Looking at your motherboard and your buses, you’ve got parallel technology and serial technology. Imagine the bits and bytes are people. With parallel, they all come running next to each other, with serial they come running right after each other. Which one is faster? Parallel right? Nope! Serial is faster. I guess the serial people are just faster…
  • SCSI is not only a way of connecting your devices, or mostly your server devices, it’s also a protocol on itself. SCSI stands for Small Computer Systems Interface. It’s a bit old and works with IDs and manual termination. SAS (serial attached SCSI) is newer and way better. Easier to configure and faster. iSCSI (internet protocol SCSI) is SCSI via Fibre or Ethernet.

Some more stuff

  • CPU cache is very limited, but super super fast. It’s on the same ‘die’ as the CPU itself. CPU cache levels are a bit of a marketing buzz but it’s true that there are CPU cache levels. Level 1 and 2 cache is small and dedicated to every CPU or core. Level 3 cache is quite a big chunk, but it is shared by all CPUs or cores.
  • Printers and I…, we’re not friends. There is a lot of printer stuff in the material for this certification. A nice fresh up was PDL which stands for Page Description Language with Postscript, or PS, that is the most known of the long list. PS is from Adobe. Other big ones are XPS by Microsoft and PCL by HP.
  • All People Seem To Need Data Processing is an acronym for the OSI (Open Systems Interconnect) model. It describes all the layers that a network packet needs to pass from host X to host Y. The layers are from top to bottom: Application – Presentation – Session – Transport – Network – Data link – Physical.

The OSI model is old material for me but very good to come across again. I will go over and over it and will surely need it in the CompTIA Network+ training and exam!

UPDATE: Also, this is awesome!

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