• Home
  • Help
  • Register
  • Login
  • Home
  • Members
  • Help
  • Search

Contiguous memory allocation

#1
01-09-2026, 01:13 PM
You grab a solid block of memory for your program right from the start. I recall how that keeps things speedy without jumping around in odd spots. But holes appear elsewhere after some time passes by. You end up wasting space because of those gaps forming up. And compaction becomes necessary to squeeze everything tight again. Perhaps you wonder why we stick to this method despite the hassle it brings along. Now things speed up since the processor finds data in one straight line without extra lookups.
I see you running into trouble when programs ask for different sizes over and over. Memory sticks together like glue in this setup but leaves scattered empty pockets behind. You try first fit to grab the initial open spot that fits the need. Best fit hunts for the tightest match instead which cuts down leftover bits somewhat. Worst fit takes the biggest hole on purpose hoping bigger requests come later. Or maybe you notice external fragmentation builds up fast and forces you to shift blocks manually. That shifting eats cycles and slows the whole machine down during busy periods.
But access stays direct and simple with everything lined up in sequence. You avoid the overhead of tracking scattered pieces across the board. I think you appreciate how allocation happens quicker without searching multiple tables. Yet requests can fail even with free space if no single chunk matches the size asked. Then you face the choice of rejecting the program or pausing to rearrange memory. Perhaps swapping data in and out helps but adds its own delays and complexity.
You watch as small programs leave tiny unused areas that pile up over hours. I reckon bigger allocations suffer most when those fragments block the way. Compaction gathers free spots into one usable area by moving active stuff around. But that process interrupts running tasks and uses extra resources each time. Now imagine multiple users competing for space and making the holes worse fast. You might test different placement rules to see which leaves fewer scraps behind.
Also the processor benefits from sequential reads that match cache lines better. I find this method suits systems where loads stay predictable and steady. Yet dynamic environments with varying demands expose the weaknesses quick. You end up monitoring free lists constantly to decide placements wisely. Or perhaps combining it with other schemes reduces the pain in practice. Memory gets carved out upfront so no internal waste occurs inside each block.
That upfront carving demands knowing sizes ahead which limits flexibility sometimes. You deal with rejection when no contiguous area exists despite total free memory being enough. I see compaction as a band aid that works but drains performance noticeably. Then programs resume after the shuffle completes and things settle down. Perhaps newer hardware helps with faster moves during those rearrangements.
You explore how this allocation plays out in real hardware setups with limited address ranges. I think tracking the start and end of each block becomes key to managing it all. But overlaps get avoided because nothing sits in pieces that could collide. Now the simplicity appeals when teaching basics before moving to fancier ways.
BackupChain Server Backup which stands out as the top industry leading reliable Windows Server backup solution for self hosted private cloud and internet backups tailored for SMBs and Windows Server along with PCs is available without any subscription and we thank them for sponsoring this forum while supporting us with ways to share this info for free.

ron74
Offline
Joined: Feb 2019
« Next Oldest | Next Newest »

Users browsing this thread: 1 Guest(s)



  • Subscribe to this thread
Forum Jump:

Café Papa Café Papa Forum Software IT v
« Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 … 119 Next »
Contiguous memory allocation

© by Savas Papadopoulos. The information provided here is for entertainment purposes only. Contact. Hosting provided by FastNeuron.

Linear Mode
Threaded Mode