diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5144353..00b29d4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Change Log
 
+## v0.12.8 - 2024-12-13
+
+### Fixed
+
+- Increase system open file limit (github #9)
+  - May simplify joint-call for large pedigrees at high thread counts
+- Improve error message when split reads map to an unknown chromosome (github #8)
+
 ## v0.12.7 - 2024-10-23
 
 ### Fixed
diff --git a/Cargo.lock b/Cargo.lock
index 7628066..1bd8cdb 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,6 +1,6 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 3
+version = 4
 
 [[package]]
 name = "adler2"
@@ -148,7 +148,7 @@ dependencies = [
  "editdistancek",
  "enum-map",
  "fxhash",
- "itertools 0.12.1",
+ "itertools 0.13.0",
  "itertools-num",
  "lazy_static",
  "multimap",
@@ -1462,6 +1462,15 @@ version = "0.8.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7a66a03ae7c801facd77a29370b4faec201768915ac14a721ba36f20bc9c209b"
 
+[[package]]
+name = "rlimit"
+version = "0.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7043b63bd0cd1aaa628e476b80e6d4023a3b50eb32789f2728908107bd0c793a"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "rmp"
 version = "0.8.14"
@@ -1610,7 +1619,7 @@ dependencies = [
 
 [[package]]
 name = "sawfish"
-version = "0.12.7"
+version = "0.12.8"
 dependencies = [
  "approx",
  "bio",
@@ -1627,6 +1636,7 @@ dependencies = [
  "num_cpus",
  "rayon",
  "regex",
+ "rlimit",
  "rmp-serde",
  "rust-htslib",
  "rust-vc-utils",
diff --git a/Cargo.toml b/Cargo.toml
index cf060b5..9af2359 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "sawfish"
-version = "0.12.7"
+version = "0.12.8"
 authors = ["Chris Saunders <csaunders@pacificbiosciences.com>"]
 description = "Structural variant analysis for mapped PacBio HiFi reads"
 edition = "2021"
@@ -32,6 +32,7 @@ num = "0.4"
 num_cpus = "1"
 rayon = "1"
 regex = "1"
+rlimit = "0"
 rust-htslib = { version = "0.47", default-features = false }
 rust-vc-utils = { path="lib/rust-vc-utils" }
 rust-wfa2 = { git = "https://github.com/ctsa/rust-wfa2.git" }
diff --git a/LICENSE-THIRDPARTY.json b/LICENSE-THIRDPARTY.json
index 9effeaa..0c8236c 100644
--- a/LICENSE-THIRDPARTY.json
+++ b/LICENSE-THIRDPARTY.json
@@ -1448,6 +1448,15 @@
     "license_file": null,
     "description": "A regular expression parser."
   },
+  {
+    "name": "rlimit",
+    "version": "0.10.2",
+    "authors": "Nugine <nugine@foxmail.com>",
+    "repository": "https://github.com/Nugine/rlimit/",
+    "license": "MIT",
+    "license_file": null,
+    "description": "Resource limits"
+  },
   {
     "name": "rmp",
     "version": "0.8.14",
@@ -1576,7 +1585,7 @@
   },
   {
     "name": "sawfish",
-    "version": "0.12.7",
+    "version": "0.12.8",
     "authors": "Chris Saunders <csaunders@pacificbiosciences.com>",
     "repository": null,
     "license": null,
diff --git a/src/bam_sa_parser.rs b/src/bam_sa_parser.rs
index cb7a3bb..0a2b887 100644
--- a/src/bam_sa_parser.rs
+++ b/src/bam_sa_parser.rs
@@ -144,7 +144,7 @@ pub fn get_seq_order_read_split_segments(
         read_size
     };
 
-    for sa_segment in sa_segments.iter() {
+    for (sa_segment_index, sa_segment) in sa_segments.iter().enumerate() {
         if !has_aligned_segments(&sa_segment.cigar) {
             let qname = std::str::from_utf8(record.qname()).unwrap().to_string();
             panic!("Bam record split segment id unaligned in read {qname}");
@@ -153,7 +153,13 @@ pub fn get_seq_order_read_split_segments(
         assert_eq!(primary_read_size, read_size);
         let (seq_order_read_start, seq_order_read_end) =
             get_seq_order_read_pos(read_start, read_end, read_size, sa_segment.is_fwd_strand);
-        let chrom_index = *chrom_list.label_to_index.get(&sa_segment.rname).unwrap();
+        let chrom_index = match chrom_list.label_to_index.get(&sa_segment.rname) {
+            Some(&x) => x,
+            None => {
+                let qname = std::str::from_utf8(record.qname()).unwrap().to_string();
+                panic!("In read '{qname}', the SA aux tag desribes a split read mapped to {}:{} (in segment {}), which is not found in the input reference fasta", sa_segment.rname, sa_segment.pos, sa_segment_index);
+            }
+        };
         seq_order_read_split_segments.push({
             SeqOrderSplitReadSegment {
                 seq_order_read_start,
diff --git a/src/main.rs b/src/main.rs
index 103f80d..57eac64 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -47,6 +47,12 @@ use crate::globals::{PROGRAM_NAME, PROGRAM_VERSION};
 use crate::joint_call::run_joint_call;
 use crate::logger::setup_output_dir_and_logger;
 
+/// Run system configuration steps prior to starting any other program logic
+///
+fn system_configuration_prelude() {
+    utils::attempt_max_open_file_limit();
+}
+
 fn run(settings: &cli::Settings) -> Result<(), Box<dyn error::Error>> {
     info!("Starting {PROGRAM_NAME} {PROGRAM_VERSION}");
     info!(
@@ -74,6 +80,8 @@ fn run(settings: &cli::Settings) -> Result<(), Box<dyn error::Error>> {
 }
 
 fn main() {
+    system_configuration_prelude();
+
     let settings = cli::validate_and_fix_settings(cli::parse_settings());
 
     // Setup logger, including creation of the output directory for the log file:
diff --git a/src/refine_sv/assemble/banded_pairwise_assembler.rs b/src/refine_sv/assemble/banded_pairwise_assembler.rs
index c99eee3..653066d 100644
--- a/src/refine_sv/assemble/banded_pairwise_assembler.rs
+++ b/src/refine_sv/assemble/banded_pairwise_assembler.rs
@@ -53,7 +53,7 @@ struct BackboneAlignmentInfo {
 // Align the next read to the backbone. If the read extends the backbone, then redefine the backbone with this extension.
 // Repeat for all reads to form a fully extended backbone.
 // Rejection scoring follows the same scheme as for POA, so we might be building multiple backbones.
-///
+//
 // 2.Pairwise POA from each backbone
 // For each backbone and its associated read set, pairwise align all reads in the set to the backbone, and take a majority vote on each edit to determine the consensus sequence.
 
diff --git a/src/spoa_utils.rs b/src/spoa_utils.rs
index 93add5a..23b7f0c 100644
--- a/src/spoa_utils.rs
+++ b/src/spoa_utils.rs
@@ -7,6 +7,7 @@ use rust_htslib::bam::record::Cigar;
 use spoa::{get_alignment_clip_size, get_alignment_overlap_size, AlignmentEngine, Graph};
 
 use crate::simple_alignment::SimpleAlignment;
+use crate::utils;
 
 /// Create a new poa graph with only the given sequence
 ///
@@ -80,7 +81,7 @@ pub fn print_msa(alignments: &[CString]) {
         assert_eq!(seq.len(), len);
     }
 
-    let rows = (len + WIDTH - 1) / WIDTH;
+    let rows = len.div_ceil(WIDTH);
 
     let ruler = {
         let mut ruler = String::new();
@@ -129,23 +130,8 @@ pub fn print_msa(alignments: &[CString]) {
 pub fn print_fasta(alignments: &[CString]) {
     const WIDTH: usize = 100;
 
-    if alignments.is_empty() {
-        return;
-    }
-
     let bytes = alignments.iter().map(|x| x.as_bytes()).collect::<Vec<_>>();
-
-    for (seq_index, seq) in bytes.iter().enumerate() {
-        let len = seq.len();
-        let rows = (len + WIDTH - 1) / WIDTH;
-
-        eprintln!("> {}", seq_index);
-        for row_index in 0..rows {
-            let start = WIDTH * row_index;
-            let end = std::cmp::min(start + WIDTH, len);
-            eprintln!("{}", std::str::from_utf8(&seq[start..end]).unwrap());
-        }
-    }
+    utils::print_fasta(WIDTH, &bytes);
 }
 
 /// Use spoa to get a consensus of two reads using the given alignment engine
diff --git a/src/utils.rs b/src/utils.rs
index 2fa48cb..44cd912 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -190,7 +190,7 @@ pub fn pairwise_alignment_printer(width: usize, lines: &[&[u8]]) {
         ruler
     };
 
-    let rows = (len + width - 1) / width;
+    let rows = len.div_ceil(width);
     for row_index in 0..rows {
         let start = width * row_index;
         let end = std::cmp::min(start + width, len);
@@ -219,7 +219,7 @@ pub fn print_fasta(width: usize, lines: &[&[u8]]) {
 
     for (seq_index, seq) in lines.iter().enumerate() {
         let len = seq.len();
-        let rows = (len + width - 1) / width;
+        let rows = len.div_ceil(width);
 
         eprintln!("> {}", seq_index);
         for row_index in 0..rows {
@@ -249,6 +249,23 @@ pub fn drop_true<T>(vec: &mut Vec<T>, drop_list: &[bool]) {
     vec.retain(|_| !*drop.next().unwrap())
 }
 
+/// Attempt to increase open file limit to the system's hard limit on *nix-like systems
+///
+/// This is an optional increase so continue through all failure cases without error.
+///
+pub fn attempt_max_open_file_limit() {
+    use rlimit::Resource;
+
+    let (soft, hard) = match Resource::NOFILE.get() {
+        Ok(x) => x,
+        Err(_) => return,
+    };
+
+    if soft < hard {
+        rlimit::setrlimit(Resource::NOFILE, hard, hard).unwrap_or_default();
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;