DVD vs HDD competition?

[apoyusiken]

Forgive my ignorance but arent they basically the same thing? Why was there a competition between the 2? (I mean performance wise apparently dvds were much better back in the day.)

[Electronics Wizardy]

There pretty different. DVDs are removable, designed to be mass produced as read only, but have very limited random IO speeds. Yea it technically can be used as random IO media with something like DVD-RAM, but its mcuh worse at it than HDD. HDDs are made for random IO and internal use within system.s

[Needfuldoer]

18 minutes ago, apoyusiken said:

Forgive my ignorance but arent they basically the same thing? Why was there a competition between the 2? (I mean performance wise apparently dvds were much better back in the day.)

DVDs and mechanical hard drives filled completely different use cases.

 

DVDs were removable storage, usually read-only, sometimes write-once (DVD-R and DVD+R), or less frequently they were rewritable. (DVD-RAM was also a thing, and those acted more like a flash drive, but they weren't day-to-day storage you booted off of.) They effectively replaced CD-ROM because they had far greater storage capacity (4.7 GB per layer instead of 700 MB per disc) at a similar manufacturing cost.

 

Hard drives did the same job back in the day as they do now: bulk data storage that can be accessed, written to, and deleted at a whim. They were what your system booted from, and where your homework folder lived.

[apoyusiken]

20 minutes ago, Needfuldoer said:

DVDs and mechanical hard drives filled completely different use cases.

 

DVDs were removable storage, usually read-only, sometimes write-once (DVD-R and DVD+R), or less frequently they were rewritable. (DVD-RAM was also a thing, and those acted more like a flash drive, but they weren't day-to-day storage you booted off of.) They effectively replaced CD-ROM because they had far greater storage capacity (4.7 GB per layer instead of 700 MB per disc) at a similar manufacturing cost.

 

Hard drives did the same job back in the day as they do now: bulk data storage that can be accessed, written to, and deleted at a whim. They were what your system booted from, and where your homework folder lived.

so basically i can think of them like different cpu architectures.

[Needfuldoer]

1 minute ago, apoyusiken said:

so basically i can think of them like different cpu architectures.

You can if you want to confuse yourself.

 

DVDs are stone tablets. Hard drives are paper notebooks.

[mariushm]

Mechanical hard drives have existed since before CDs and DVDs, and their purpose was to hold programs and data that would not fit on floppy disks.

 

Mechanical drives can read and write basically an infinite number of times, and they can store data onto multiple platters (discs). You get access to the data as soon as the read/write heads move above the track and as soon as the platters spin for the data to reach under the head.

 

They made read only CDs and only later they invented the chemicals and the method to write CDs and rewrite them, and you can't rewrite them a lot ... at most you're looking at up to 1000 erases / rewrites.

 

DVD drives spin the plastic discs at lower speeds and are slower at seeking data (laser and sensor move slower), and the plastic discs can wobble, can be scratched...

 

 

[Ryker Robb]

16 hours ago, apoyusiken said:

Forgive my ignorance but arent they basically the same thing? Why was there a competition between the 2? (I mean performance wise apparently dvds were much better back in the day.)

Dvds are optical storage (reflecting lasers off the disk), while hdd's are magnetic storage (detecting changing magnetic polarities via a magnetoresistance type head).