Please navigate by using our sitemap if a new menu does not appear shortly.

A ramdisk ( or ramdisc ) filesystem stores data directly to memory
instead of a hard disk drive providing the fastest data I/O available
to increase performance of applications.  All of the standard hp-ux
data access commands are compatible with ramdisc filesystems.

Why is a ramdisc faster than a conventional disk drive?

A ramdisc has no mechanical moving parts and  all data is stored
in main system memory.   A disk drive  stores data on platters that
spin at  a high rpm with  read and write  heads that move across a
set of platters to access the data. The animated image represents
the method that data is retrieved.  Move your  mouse over  the disk
drive  to  start  the  animation.  The  red colored  dots  represent  a
request for data.  The drive heads read the  VTOC ( Volume Table
Of Contents ) then move to a location on the platter where the data
is stored.  Depending on rotation,  the read head may have to wait
for another revolution before it can  read or write any of the data on
the  platters.  The  yellow colored  dots  represent  the  data being
sent back to the  system. If you remove the mechanical limitations
by using a  solid state disk,  your performance will improve but not
to the degree of a ramdisc due to SCSI bus or PCI bus speeds as
compared  to the speed of a memory bus.  The image on the right
is a disk drive with the top cover removed.  Your data  is more than
likely  not stored  sequentially on the  platters  so there  are delays
within a busy disk drive to retrieve or write the data as well.

hard disk drive animation
hard disk drive exposed
What happens to a ramdisc filesystem when the power goes out?  In the past, this question may
have been more difficult to answer. Most users want to have that "warm and fuzzy feeling" that the data
is safe and secure which usually tends to sacrifice speed for security. Using the security advantages of
MirrorDisk/UX combined with the speed of a ramdisc, you can now have both speed and data integrity
using our software package referred to as RamDisc Plus.

The RamDisc Plus package ¹ allows you to:
  • Create volume group(s) with system memory and two hard disk drives.
  • The ramdisc and hard drives become a mirrored set using MirrorDisk/UX. ²
  • Configure logical volumes including disk drive only mirrored volumes.
  • Write data to the volume group (ramdisc and both hard drives) simultaneously.
  • Automatically restore mirrored data to ramdisc despite power outage, crash, shutdowns or reboots.
  • Create Ram Only volume group(s) with multiple mount points without using MirrorDisk/UX ²
  • Use as a RAW device for database access (used with Ram Only or MirrorDisk/UX).
  • Deallocate the memory that was used for a ramdisc without rebooting the system.

    The RamCluster package (part of RamDisc Plus) allows you to:
  • Create MC/ServiceGuard ³ clustered volume groups using memory and RAID LUN(s).
  • Allow RamDisc volume groups to failover between primary to alternate systems.
  • Data within the RamDisc configuration is available immediately upon failover.

    ¹  RamDisc Plus contains all of the functionality of RamDisc Classic.
    ²  MirrorDisk/UX is an optional software product from Hewlett-Packard.
    ³  MC/ServiceGuard is an optional software product from Hewlett-Packard.

    RamDisc Plus is available for download here  and  FAQs are available here.        Updated URLs

    RamDisc pricing is based upon the memory range of usage shown in the chart below. A new tool has
    been developed to provide flexible pricing based upon the actual amount of memory  (in 1GB portions)
    reserved for RamDisc configurations.  This tool also calculates a future  RamDisc upgrade  as well as
    multiple sysytem  discounts  and supports  memory  ranges up to 512GB  (using HPUX 11.23 11i v2 ).

  • RamDisc Plus price chart
    RamDisc Usage ¹         GigaBytes                          Purchase Price                          Support  Price ² 
    32MB -  256MB  0.25 GB $ 310.00 $ 175.00 
    257MB -  512MB    0.50 GB $ 790.00 $ 220.00 
    513MB -  1024MB  1GB $ 1,950.00 $ 285.00 
    1025MB -  2048MB    2GB $ 3,100.00 $ 355.00 
    2049MB -  4096MB  4GB $ 4,140.00 $ 420.00 
    4097MB -  8192MB    8GB $ 5,625.00 $ 530.00 
    8193MB -  16384MB  16GB $ 8,100.00 $ 705.00 
    16385MB -  32704MB¹   32GB $ 12,150.00 $ 965.00 

    ¹  The maximum amount of memory that RamDisc may use  (except version 11.23 11i v2 )
    ²  Annual support includes technical support, product enhancements and emergency license replacement.
    ³  One runtime license per hp-ux system within a single purchase or contract. Prices shown are per system.

    Download RamDisc plus for hp-ux             Release Notes           FAQs
    Try an online conventional disk drive and RamDisc Classic comparison.
    View an EVA8000 (SAN) and RamDisc Plus benchmark utility comparison.
    View the VA7400 Virtual RAID array and RamDisc Plus IOzone comparison results.
    View 4.7ms 10,000 rpm LVD disk and  RamDisc Plus benchmark utility comparison.
    View 3.6ms 15,000 rpm Ultra320 IA64 RamDisc Plus benchmark utility comparison.
    Some possible scenarios where your application may benefit from using RamDisc.

    Our original software package is now referred to as RamDisc Classic and is still
    available for earlier HP-UX OS revisions  9.05 - 10.10.

    Other pages within the AppMate website...
    [Home]  [Software]  [Contact Us]  [References]  [Geek stuff]
    AppMate Performance Software
    207 Long Pond Rd
    Danville, NH 03819
    Tel: (603) 617-2833
    Fax: (603) 617-2891
    Tel: (888) 601-3069